1 | # cosmiconfig
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2 |
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3 | [![codecov](https://codecov.io/gh/cosmiconfig/cosmiconfig/branch/main/graph/badge.svg)](https://codecov.io/gh/cosmiconfig/cosmiconfig)
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4 |
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5 | Cosmiconfig searches for and loads configuration for your program.
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6 |
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7 | It features smart defaults based on conventional expectations in the JavaScript ecosystem.
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8 | But it's also flexible enough to search wherever you'd like to search, and load whatever you'd like to load.
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9 |
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10 | By default, Cosmiconfig will check the current directory for the following:
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11 |
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12 | - a `package.json` property
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13 | - a JSON or YAML, extensionless "rc file"
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14 | - an "rc file" with the extensions `.json`, `.yaml`, `.yml`, `.js`, `.ts`, `.mjs`, or `.cjs`
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15 | - any of the above two inside a `.config` subdirectory
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16 | - a `.config.js`, `.config.ts`, `.config.mjs`, or `.config.cjs` file
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17 |
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18 | For example, if your module's name is "myapp", cosmiconfig will search up the directory tree for configuration in the following places:
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19 |
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20 | - a `myapp` property in `package.json`
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21 | - a `.myapprc` file in JSON or YAML format
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22 | - a `.myapprc.json`, `.myapprc.yaml`, `.myapprc.yml`, `.myapprc.js`, `.myapprc.ts`, `.myapprc.mjs`, or `.myapprc.cjs` file
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23 | - a `myapprc`, `myapprc.json`, `myapprc.yaml`, `myapprc.yml`, `myapprc.js`, `myapprc.ts`, `myapprc.mjs`, or `myapprc.cjs` file inside a `.config` subdirectory
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24 | - a `myapp.config.js`, `myapp.config.ts`, `myapp.config.mjs`, or `myapp.config.cjs` file
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25 |
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26 | Optionally, you can tell it to search up the directory tree using [search strategies],
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27 | checking each of these places in each directory, until it finds some acceptable configuration (or hits the home directory).
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28 |
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29 | ## Table of contents
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30 |
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31 | - [Installation](#installation)
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32 | - [Usage for tooling developers](#usage-for-tooling-developers)
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33 | - [Result](#result)
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34 | - [Asynchronous API](#asynchronous-api)
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35 | - [cosmiconfig()](#cosmiconfig-1)
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36 | - [explorer.search()](#explorersearch)
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37 | - [explorer.load()](#explorerload)
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38 | - [explorer.clearLoadCache()](#explorerclearloadcache)
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39 | - [explorer.clearSearchCache()](#explorerclearsearchcache)
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40 | - [explorer.clearCaches()](#explorerclearcaches)
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41 | - [Synchronous API](#synchronous-api)
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42 | - [cosmiconfigSync()](#cosmiconfigsync)
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43 | - [explorerSync.search()](#explorersyncsearch)
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44 | - [explorerSync.load()](#explorersyncload)
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45 | - [explorerSync.clearLoadCache()](#explorersyncclearloadcache)
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46 | - [explorerSync.clearSearchCache()](#explorersyncclearsearchcache)
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47 | - [explorerSync.clearCaches()](#explorersyncclearcaches)
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48 | - [cosmiconfigOptions](#cosmiconfigoptions)
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49 | - [searchStrategy](#searchstrategy)
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50 | - [searchPlaces](#searchplaces)
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51 | - [loaders](#loaders)
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52 | - [packageProp](#packageprop)
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53 | - [stopDir](#stopdir)
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54 | - [cache](#cache)
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55 | - [transform](#transform)
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56 | - [ignoreEmptySearchPlaces](#ignoreemptysearchplaces)
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57 | - [Loading JS modules](#loading-js-modules)
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58 | - [Caching](#caching)
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59 | - [Differences from rc](#differences-from-rc)
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60 | - [Usage for end users](#usage-for-end-users)
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61 | - [Imports](#imports)
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62 | - [Contributing & Development](#contributing--development)
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63 |
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64 | ## Installation
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65 |
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66 | ```
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67 | npm install cosmiconfig
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68 | ```
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69 |
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70 | Tested in Node 14+.
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71 |
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72 | ## Usage for tooling developers
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73 |
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74 | *If you are an end user (i.e. a user of a tool that uses cosmiconfig, like `prettier` or `stylelint`),
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75 | you can skip down to [the end user section](#usage-for-end-users).*
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76 |
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77 | Create a Cosmiconfig explorer, then either `search` for or directly `load` a configuration file.
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78 |
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79 | ```js
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80 | const { cosmiconfig, cosmiconfigSync } = require('cosmiconfig');
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81 | // ...
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82 | const explorer = cosmiconfig(moduleName);
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83 |
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84 | // Search for a configuration by walking up directories.
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85 | // See documentation for search, below.
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86 | explorer.search()
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87 | .then((result) => {
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88 | // result.config is the parsed configuration object.
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89 | // result.filepath is the path to the config file that was found.
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90 | // result.isEmpty is true if there was nothing to parse in the config file.
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91 | })
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92 | .catch((error) => {
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93 | // Do something constructive.
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94 | });
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95 |
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96 | // Load a configuration directly when you know where it should be.
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97 | // The result object is the same as for search.
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98 | // See documentation for load, below.
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99 | explorer.load(pathToConfig).then(/* ... */);
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100 |
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101 | // You can also search and load synchronously.
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102 | const explorerSync = cosmiconfigSync(moduleName);
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103 |
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104 | const searchedFor = explorerSync.search();
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105 | const loaded = explorerSync.load(pathToConfig);
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106 | ```
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107 |
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108 | ## Result
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109 |
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110 | The result object you get from `search` or `load` has the following properties:
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111 |
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112 | - **config:** The parsed configuration object. `undefined` if the file is empty.
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113 | - **filepath:** The path to the configuration file that was found.
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114 | - **isEmpty:** `true` if the configuration file is empty. This property will not be present if the configuration file is not empty.
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115 |
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116 | ## Asynchronous API
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117 |
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118 | ### cosmiconfig()
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119 |
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120 | ```js
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121 | const { cosmiconfig } = require('cosmiconfig');
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122 | const explorer = cosmiconfig(moduleName, /* optional */ cosmiconfigOptions)
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123 | ```
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124 |
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125 | Creates a cosmiconfig instance ("explorer") configured according to the arguments, and initializes its caches.
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126 |
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127 | #### moduleName
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128 |
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129 | Type: `string`. **Required.**
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130 |
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131 | Your module name. This is used to create the default [`searchPlaces`] and [`packageProp`].
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132 |
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133 | If your [`searchPlaces`] value will include files, as it does by default (e.g. `${moduleName}rc`), your `moduleName` must consist of characters allowed in filenames. That means you should not copy scoped package names, such as `@my-org/my-package`, directly into `moduleName`.
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134 |
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135 | **[`cosmiconfigOptions`] are documented below.**
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136 | You may not need them, and should first read about the functions you'll use.
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137 |
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138 | ### explorer.search()
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139 |
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140 | ```js
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141 | explorer.search([searchFrom]).then(result => { /* ... */ })
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142 | ```
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143 |
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144 | Searches for a configuration file. Returns a Promise that resolves with a [result] or with `null`, if no configuration file is found.
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145 |
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146 | You can do the same thing synchronously with [`explorerSync.search()`].
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147 |
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148 | Let's say your module name is `goldengrahams` so you initialized with `const explorer = cosmiconfig('goldengrahams');`.
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149 | Here's how your default [`search()`] will work:
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150 |
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151 | - Starting from `process.cwd()` (or some other directory defined by the `searchFrom` argument to [`search()`]), look for configuration objects in the following places:
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152 | 1. A `goldengrahams` property in a `package.json` file.
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153 | 2. A `.goldengrahamsrc` file with JSON or YAML syntax.
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154 | 3. A `.goldengrahamsrc.json`, `.goldengrahamsrc.yaml`, `.goldengrahamsrc.yml`, `.goldengrahamsrc.js`, `.goldengrahamsrc.ts`, `.goldengrahamsrc.mjs`, or `.goldengrahamsrc.cjs` file. (To learn more about how JS files are loaded, see ["Loading JS modules"].)
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155 | 4. A `goldengrahamsrc`, `goldengrahamsrc.json`, `goldengrahamsrc.yaml`, `goldengrahamsrc.yml`, `goldengrahamsrc.js`, `goldengrahamsrc.ts`, `goldengrahamsrc.mjs`, or `goldengrahamsrc.cjs` file in the `.config` subdirectory.
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156 | 5. A `goldengrahams.config.js`, `goldengrahams.config.ts`, `goldengrahams.config.mjs`, or `goldengrahams.config.cjs` file. (To learn more about how JS files are loaded, see ["Loading JS modules"].)
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157 | - If none of those searches reveal a configuration object, continue depending on the current search strategy:
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158 | - If it's `none` (which is the default if you don't specify a [`stopDir`] option), stop here and return/resolve with `null`.
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159 | - If it's `global` (which is the default if you specify a [`stopDir`] option), move up one directory level and try again,
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160 | recursing until arriving at the configured [`stopDir`] option, which defaults to the user's home directory.
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161 | - After arriving at the [`stopDir`], the global configuration directory (as defined by [`env-paths`] without prefix) is also checked,
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162 | looking at the files `config`, `config.json`, `config.yaml`, `config.yml`, `config.js`, `config.ts`, `config.cjs`, and `config.mjs`
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163 | in the directory `~/.config/goldengrahams/` (on Linux; see [`env-paths`] documentation for other OSs).
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164 | - If it's `project`, check whether a `package.json` file is present in the current directory, and if not,
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165 | move up one directory level and try again, recursing until there is one.
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166 | - If at any point a parsable configuration is found, the [`search()`] Promise resolves with its [result] \(or, with [`explorerSync.search()`], the [result] is returned).
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167 | - If no configuration object is found, the [`search()`] Promise resolves with `null` (or, with [`explorerSync.search()`], `null` is returned).
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168 | - If a configuration object is found *but is malformed* (causing a parsing error), the [`search()`] Promise rejects with that error (so you should `.catch()` it). (Or, with [`explorerSync.search()`], the error is thrown.)
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169 |
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170 | **If you know exactly where your configuration file should be, you can use [`load()`], instead.**
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171 |
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172 | **The search process is highly customizable.**
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173 | Use the cosmiconfig options [`searchPlaces`] and [`loaders`] to precisely define where you want to look for configurations and how you want to load them.
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174 |
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175 | #### searchFrom
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176 |
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177 | Type: `string`.
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178 | Default: `process.cwd()`.
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179 |
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180 | A filename.
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181 | [`search()`] will start its search here.
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182 |
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183 | If the value is a directory, that's where the search starts.
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184 | If it's a file, the search starts in that file's directory.
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185 |
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186 | ### explorer.load()
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187 |
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188 | ```js
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189 | explorer.load(loadPath).then(result => { /* ... */ })
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190 | ```
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191 |
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192 | Loads a configuration file. Returns a Promise that resolves with a [result] or rejects with an error (if the file does not exist or cannot be loaded).
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193 |
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194 | Use `load` if you already know where the configuration file is and you just need to load it.
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195 |
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196 | ```js
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197 | explorer.load('load/this/file.json'); // Tries to load load/this/file.json.
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198 | ```
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199 |
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200 | If you load a `package.json` file, the result will be derived from whatever property is specified as your [`packageProp`].
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201 | `package.yaml` will work as well if you specify these file names in your [`searchPlaces`].
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202 |
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203 | You can do the same thing synchronously with [`explorerSync.load()`].
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204 |
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205 | ### explorer.clearLoadCache()
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206 |
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207 | Clears the cache used in [`load()`].
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208 |
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209 | ### explorer.clearSearchCache()
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210 |
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211 | Clears the cache used in [`search()`].
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212 |
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213 | ### explorer.clearCaches()
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214 |
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215 | Performs both [`clearLoadCache()`] and [`clearSearchCache()`].
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216 |
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217 | ## Synchronous API
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218 |
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219 | ### cosmiconfigSync()
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220 |
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221 | ```js
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222 | const { cosmiconfigSync } = require('cosmiconfig');
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223 | const explorerSync = cosmiconfigSync(moduleName, /* optional */ cosmiconfigOptions)
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224 | ```
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225 |
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226 | Creates a *synchronous* cosmiconfig instance ("explorerSync") configured according to the arguments, and initializes its caches.
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227 |
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228 | See [`cosmiconfig()`](#cosmiconfig-1).
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229 |
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230 | ### explorerSync.search()
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231 |
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232 | ```js
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233 | const result = explorerSync.search([searchFrom]);
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234 | ```
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235 |
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236 | Synchronous version of [`explorer.search()`].
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237 |
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238 | Returns a [result] or `null`.
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239 |
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240 | ### explorerSync.load()
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241 |
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242 | ```js
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243 | const result = explorerSync.load(loadPath);
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244 | ```
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245 |
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246 | Synchronous version of [`explorer.load()`].
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247 |
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248 | Returns a [result].
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249 |
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250 | ### explorerSync.clearLoadCache()
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251 |
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252 | Clears the cache used in [`load()`].
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253 |
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254 | ### explorerSync.clearSearchCache()
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255 |
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256 | Clears the cache used in [`search()`].
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257 |
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258 | ### explorerSync.clearCaches()
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259 |
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260 | Performs both [`clearLoadCache()`] and [`clearSearchCache()`].
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261 |
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262 | ## cosmiconfigOptions
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263 |
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264 | Type: `Object`.
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265 |
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266 | Possible options are documented below.
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267 |
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268 | ### searchStrategy
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269 |
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270 | Type: `string`
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271 | Default: `global` if [`stopDir`] is specified, `none` otherwise.
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272 |
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273 | The strategy that should be used to determine which directories to check for configuration files.
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274 |
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275 | - `none`: Only checks in the current working directory.
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276 | - `project`: Starts in the current working directory, traversing upwards until a `package.{json,yaml}` file is found.
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277 | - `global`: Starts in the current working directory, traversing upwards until the configured [`stopDir`]
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278 | (or the current user's home directory if none is given). Then, if no configuration is found, also look in the
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279 | operating system's default configuration directory (according to [`env-paths`] without prefix),
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280 | where a different set of file names is checked:
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281 |
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282 | ```js
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283 | [
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284 | `config`,
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285 | `config.json`,
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286 | `config.yaml`,
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287 | `config.yml`,
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288 | `config.js`,
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289 | `config.ts`,
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290 | `config.cjs`,
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291 | `config.mjs`
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292 | ]
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293 | ```
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294 |
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295 | ### searchPlaces
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296 |
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297 | Type: `Array<string>`.
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298 | Default: See below.
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299 |
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300 | An array of places that [`search()`] will check in each directory as it moves up the directory tree.
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301 | Each place is relative to the directory being searched, and the places are checked in the specified order.
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302 |
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303 | **Default `searchPlaces`:**
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304 |
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305 | For the [asynchronous API](#asynchronous-api), these are the default `searchPlaces`:
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306 |
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307 | ```js
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308 | [
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309 | 'package.json',
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310 | `.${moduleName}rc`,
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311 | `.${moduleName}rc.json`,
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312 | `.${moduleName}rc.yaml`,
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313 | `.${moduleName}rc.yml`,
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314 | `.${moduleName}rc.js`,
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315 | `.${moduleName}rc.ts`,
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316 | `.${moduleName}rc.mjs`,
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317 | `.${moduleName}rc.cjs`,
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318 | `.config/${moduleName}rc`,
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319 | `.config/${moduleName}rc.json`,
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320 | `.config/${moduleName}rc.yaml`,
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321 | `.config/${moduleName}rc.yml`,
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322 | `.config/${moduleName}rc.js`,
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323 | `.config/${moduleName}rc.ts`,
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324 | `.config/${moduleName}rc.mjs`,
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325 | `.config/${moduleName}rc.cjs`,
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326 | `${moduleName}.config.js`,
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327 | `${moduleName}.config.ts`,
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328 | `${moduleName}.config.mjs`,
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329 | `${moduleName}.config.cjs`,
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330 | ];
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331 | ```
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332 |
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333 | For the [synchronous API](#synchronous-api), the only difference is that `.mjs` files are not included. See ["Loading JS modules"] for more information.
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334 |
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335 | Create your own array to search more, fewer, or altogether different places.
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336 |
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337 | Every item in `searchPlaces` needs to have a loader in [`loaders`] that corresponds to its extension.
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338 | (Common extensions are covered by default loaders.)
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339 | Read more about [`loaders`] below.
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340 |
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341 | `package.json` is a special value: When it is included in `searchPlaces`, Cosmiconfig will always parse it as JSON and load a property within it, not the whole file.
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342 | That property is defined with the [`packageProp`] option, and defaults to your module name.
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343 |
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344 | `package.yaml` (used by pnpm) works the same way.
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345 |
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346 | Examples, with a module named `porgy`:
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347 |
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348 | ```js
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349 | // Disallow extensions on rc files:
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350 | ['package.json', '.porgyrc', 'porgy.config.js']
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351 | ```
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352 |
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353 | ```js
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354 | // Limit the options dramatically:
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355 | ['package.json', '.porgyrc']
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356 | ```
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357 |
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358 | ```js
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359 | // Maybe you want to look for a wide variety of JS flavors:
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360 | [
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361 | 'porgy.config.js',
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362 | 'porgy.config.mjs',
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363 | 'porgy.config.ts',
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364 | 'porgy.config.coffee'
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365 | ]
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366 | // ^^ You will need to designate a custom loader to tell
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367 | // Cosmiconfig how to handle `.coffee` files.
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368 | ```
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369 |
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370 | ```js
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371 | // Look within a .config/ subdirectory of every searched directory:
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372 | [
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373 | 'package.json',
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374 | '.porgyrc',
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375 | '.config/.porgyrc',
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376 | '.porgyrc.json',
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377 | '.config/.porgyrc.json'
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378 | ]
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379 | ```
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380 |
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381 | ### loaders
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382 |
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383 | Type: `Object`.
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384 | Default: See below.
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385 |
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386 | An object that maps extensions to the loader functions responsible for loading and parsing files with those extensions.
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387 |
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388 | Cosmiconfig exposes its default loaders on the named export `defaultLoaders` and `defaultLoadersSync`.
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389 |
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390 | **Default `loaders`:**
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391 |
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392 | ```js
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393 | const { defaultLoaders, defaultLoadersSync } = require('cosmiconfig');
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394 |
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395 | console.log(Object.entries(defaultLoaders));
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396 | // [
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397 | // [ '.mjs', [Function: loadJs] ],
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398 | // [ '.cjs', [Function: loadJs] ],
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399 | // [ '.js', [Function: loadJs] ],
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400 | // [ '.ts', [Function: loadTs] ],
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401 | // [ '.json', [Function: loadJson] ],
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402 | // [ '.yaml', [Function: loadYaml] ],
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403 | // [ '.yml', [Function: loadYaml] ],
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404 | // [ 'noExt', [Function: loadYaml] ]
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405 | // ]
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406 |
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407 | console.log(Object.entries(defaultLoadersSync));
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408 | // [
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409 | // [ '.cjs', [Function: loadJsSync] ],
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410 | // [ '.js', [Function: loadJsSync] ],
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411 | // [ '.ts', [Function: loadTsSync] ],
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412 | // [ '.json', [Function: loadJson] ],
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413 | // [ '.yaml', [Function: loadYaml] ],
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414 | // [ '.yml', [Function: loadYaml] ],
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415 | // [ 'noExt', [Function: loadYaml] ]
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416 | // ]
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417 | ```
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418 |
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419 | (YAML is a superset of JSON; which means YAML parsers can parse JSON; which is how extensionless files can be either YAML *or* JSON with only one parser.)
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420 |
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421 | **If you provide a `loaders` object, your object will be *merged* with the defaults.**
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422 | So you can override one or two without having to override them all.
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423 |
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424 | **Keys in `loaders`** are extensions (starting with a period), or `noExt` to specify the loader for files *without* extensions, like `.myapprc`.
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425 |
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426 | **Values in `loaders`** are a loader function (described below) whose values are loader functions.
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427 |
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428 | **The most common use case for custom loaders value is to load extensionless `rc` files as strict JSON**, instead of JSON *or* YAML (the default).
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429 | To accomplish that, provide the following `loaders` value:
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430 |
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431 | ```js
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432 | {
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433 | noExt: defaultLoaders['.json'];
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434 | }
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435 | ```
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436 |
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437 | If you want to load files that are not handled by the loader functions Cosmiconfig exposes, you can write a custom loader function or use one from NPM if it exists.
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438 |
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439 | **Use cases for custom loader function:**
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440 |
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441 | - Allow configuration syntaxes that aren't handled by Cosmiconfig's defaults, like JSON5, INI, or XML.
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442 | - Parse JS files with Babel before deriving the configuration.
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443 |
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444 | **Custom loader functions** have the following signature:
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445 |
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446 | ```ts
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447 | // Sync
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448 | type SyncLoader = (filepath: string, content: string) => Object | null
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449 |
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450 | // Async
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451 | type AsyncLoader = (filepath: string, content: string) => Object | null | Promise<Object | null>
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452 | ```
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453 |
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454 | Cosmiconfig reads the file when it checks whether the file exists, so it will provide you with both the file's path and its content.
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455 | Do whatever you need to, and return either a configuration object or `null` (or, for async-only loaders, a Promise that resolves with one of those).
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456 | `null` indicates that no real configuration was found and the search should continue.
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457 |
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458 | A few things to note:
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459 |
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460 | - If you use a custom loader, be aware of whether it's sync or async: you cannot use async customer loaders with the sync API ([`cosmiconfigSync()`]).
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461 | - **Special JS syntax can also be handled by using a `require` hook**, because `defaultLoaders['.js']` just uses `require`.
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462 | Whether you use custom loaders or a `require` hook is up to you.
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463 |
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464 | Examples:
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465 |
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466 | ```js
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467 | // Allow JSON5 syntax:
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468 | cosmiconfig('foo', {
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469 | loaders: {
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470 | '.json': json5Loader
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471 | }
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472 | });
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473 |
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474 | // Allow a special configuration syntax of your own creation:
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475 | cosmiconfig('foo', {
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476 | loaders: {
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477 | '.special': specialLoader
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478 | }
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479 | });
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480 |
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481 | // Allow many flavors of JS, using custom loaders:
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482 | cosmiconfig('foo', {
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483 | loaders: {
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484 | '.coffee': coffeeScriptLoader
|
485 | }
|
486 | });
|
487 |
|
488 | // Allow many flavors of JS but rely on require hooks:
|
489 | cosmiconfig('foo', {
|
490 | loaders: {
|
491 | '.coffee': defaultLoaders['.js']
|
492 | }
|
493 | });
|
494 | ```
|
495 |
|
496 | ### packageProp
|
497 |
|
498 | Type: `string | Array<string>`.
|
499 | Default: `` `${moduleName}` ``.
|
500 |
|
501 | Name of the property in `package.json` (or `package.yaml`) to look for.
|
502 |
|
503 | Use a period-delimited string or an array of strings to describe a path to nested properties.
|
504 |
|
505 | For example, the value `'configs.myPackage'` or `['configs', 'myPackage']` will get you the `"myPackage"` value in a `package.json` like this:
|
506 |
|
507 | ```json
|
508 | {
|
509 | "configs": {
|
510 | "myPackage": {"option": "value"}
|
511 | }
|
512 | }
|
513 | ```
|
514 |
|
515 | If nested property names within the path include periods, you need to use an array of strings. For example, the value `['configs', 'foo.bar', 'baz']` will get you the `"baz"` value in a `package.json` like this:
|
516 |
|
517 | ```json
|
518 | {
|
519 | "configs": {
|
520 | "foo.bar": {
|
521 | "baz": {"option": "value"}
|
522 | }
|
523 | }
|
524 | }
|
525 | ```
|
526 |
|
527 | If a string includes period but corresponds to a top-level property name, it will not be interpreted as a period-delimited path. For example, the value `'one.two'` will get you the `"three"` value in a `package.json` like this:
|
528 |
|
529 | ```json
|
530 | {
|
531 | "one.two": "three",
|
532 | "one": {
|
533 | "two": "four"
|
534 | }
|
535 | }
|
536 | ```
|
537 |
|
538 | ### stopDir
|
539 |
|
540 | Type: `string`.
|
541 | Default: Absolute path to your home directory.
|
542 |
|
543 | Directory where the search will stop.
|
544 |
|
545 | ### cache
|
546 |
|
547 | Type: `boolean`.
|
548 | Default: `true`.
|
549 |
|
550 | If `false`, no caches will be used.
|
551 | Read more about ["Caching"](#caching) below.
|
552 |
|
553 | ### transform
|
554 |
|
555 | Type: `(Result) => Promise<Result> | Result`.
|
556 |
|
557 | A function that transforms the parsed configuration. Receives the [result].
|
558 |
|
559 | If using [`search()`] or [`load()`] \(which are async), the transform function can return the transformed result or return a Promise that resolves with the transformed result.
|
560 | If using `cosmiconfigSync`, [`search()`] or [`load()`], the function must be synchronous and return the transformed result.
|
561 |
|
562 | The reason you might use this option — instead of simply applying your transform function some other way — is that *the transformed result will be cached*. If your transformation involves additional filesystem I/O or other potentially slow processing, you can use this option to avoid repeating those steps every time a given configuration is searched or loaded.
|
563 |
|
564 | ### ignoreEmptySearchPlaces
|
565 |
|
566 | Type: `boolean`.
|
567 | Default: `true`.
|
568 |
|
569 | By default, if [`search()`] encounters an empty file (containing nothing but whitespace) in one of the [`searchPlaces`], it will ignore the empty file and move on.
|
570 | If you'd like to load empty configuration files, instead, set this option to `false`.
|
571 |
|
572 | Why might you want to load empty configuration files?
|
573 | If you want to throw an error, or if an empty configuration file means something to your program.
|
574 |
|
575 | ## Loading JS modules
|
576 |
|
577 | Your end users can provide JS configuration files as ECMAScript modules (ESM) under the following conditions:
|
578 |
|
579 | - You (the cosmiconfig user) use cosmiconfig's [asynchronous API](#asynchronous-api).
|
580 | - Your end user runs a version of Node that supports ESM ([>=12.17.0](https://nodejs.org/en/blog/release/v12.17.0/), or earlier with the `--experimental-modules` flag).
|
581 | - Your end user provides an `.mjs` configuration file, or a `.js` file whose nearest parent `package.json` file contains `"type": "module"`. (See [Node's method for determining a file's module system](https://nodejs.org/api/packages.html#packages_determining_module_system).)
|
582 |
|
583 | With cosmiconfig's [asynchronous API](#asynchronous-api), the default [`searchPlaces`] include `.js`, `.ts`, `.mjs`, and `.cjs` files. Cosmiconfig loads all these file types with the [dynamic `import` function](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/import#dynamic_imports).
|
584 |
|
585 | With the [synchronous API](#synchronous-api), JS configuration files are always treated as CommonJS, and `.mjs` files are ignored, because there is no synchronous API for the dynamic `import` function.
|
586 |
|
587 | ## Caching
|
588 |
|
589 | As of v2, cosmiconfig uses caching to reduce the need for repetitious reading of the filesystem or expensive transforms. Every new cosmiconfig instance (created with `cosmiconfig()`) has its own caches.
|
590 |
|
591 | To avoid or work around caching, you can do the following:
|
592 |
|
593 | - Set the `cosmiconfig` option [`cache`] to `false`.
|
594 | - Use the cache-clearing methods [`clearLoadCache()`], [`clearSearchCache()`], and [`clearCaches()`].
|
595 | - Create separate instances of cosmiconfig (separate "explorers").
|
596 |
|
597 | ## Differences from [rc](https://github.com/dominictarr/rc)
|
598 |
|
599 | [rc](https://github.com/dominictarr/rc) serves its focused purpose well. cosmiconfig differs in a few key ways — making it more useful for some projects, less useful for others:
|
600 |
|
601 | - Looks for configuration in some different places: in a `package.json` property, an rc file, a `.config.js` file, and rc files with extensions.
|
602 | - Built-in support for JSON, YAML, and CommonJS formats.
|
603 | - Stops at the first configuration found, instead of finding all that can be found up the directory tree and merging them automatically.
|
604 | - Options.
|
605 | - Asynchronous by default (though can be run synchronously).
|
606 |
|
607 | ## Usage for end users
|
608 |
|
609 | When configuring a tool, you can use multiple file formats and put these in multiple places.
|
610 |
|
611 | Usually, a tool would mention this in its own README file,
|
612 | but by default, these are the following places, where `{NAME}` represents the name of the tool:
|
613 |
|
614 | ```
|
615 | package.json
|
616 | .{NAME}rc
|
617 | .{NAME}rc.json
|
618 | .{NAME}rc.yaml
|
619 | .{NAME}rc.yml
|
620 | .{NAME}rc.js
|
621 | .{NAME}rc.ts
|
622 | .{NAME}rc.cjs
|
623 | .config/{NAME}rc
|
624 | .config/{NAME}rc.json
|
625 | .config/{NAME}rc.yaml
|
626 | .config/{NAME}rc.yml
|
627 | .config/{NAME}rc.js
|
628 | .config/{NAME}rc.ts
|
629 | .config/{NAME}rc.mjs
|
630 | .config/{NAME}rc.cjs
|
631 | {NAME}.config.js
|
632 | {NAME}.config.ts
|
633 | {NAME}.config.mjs
|
634 | {NAME}.config.cjs
|
635 | ```
|
636 |
|
637 | The contents of these files are defined by the tool.
|
638 | For example, you can configure prettier to enforce semicolons at the end of the line
|
639 | using a file named `.config/prettierrc.yml`:
|
640 |
|
641 | ```yaml
|
642 | semi: true
|
643 | ```
|
644 |
|
645 | Additionally, you have the option to put a property named after the tool in your `package.json` file,
|
646 | with the contents of that property being the same as the file contents. To use the same example as above:
|
647 |
|
648 | ```json
|
649 | {
|
650 | "name": "your-project",
|
651 | "dependencies": {},
|
652 | "prettier": {
|
653 | "semi": true
|
654 | }
|
655 | }
|
656 | ```
|
657 |
|
658 | This has the advantage that you can put the configuration of all tools
|
659 | (at least the ones that use cosmiconfig) in one file.
|
660 |
|
661 | You can also add a `cosmiconfig` key within your `package.json` file or create one of the following files
|
662 | to configure `cosmiconfig` itself:
|
663 |
|
664 | ```
|
665 | .config/config.json
|
666 | .config/config.yaml
|
667 | .config/config.yml
|
668 | .config/config.js
|
669 | .config/config.ts
|
670 | .config/config.cjs
|
671 | ```
|
672 |
|
673 | The following properties are currently actively supported in these places:
|
674 |
|
675 | ```yaml
|
676 | cosmiconfig:
|
677 | # adds places where configuration files are being searched
|
678 | searchPlaces:
|
679 | - .config/{name}.yml
|
680 | # to enforce a custom naming convention and format, don't merge the above with the tool-defined search places
|
681 | # (`true` is the default setting)
|
682 | mergeSearchPlaces: false
|
683 | ```
|
684 |
|
685 | > **Note:** technically, you can overwrite all options described in [cosmiconfigOptions](#cosmiconfigoptions) here,
|
686 | > but everything not listed above should be used at your own risk, as it has not been tested explicitly.
|
687 | > The only exceptions to this are the `loaders` property, which is explicitly not supported at this time,
|
688 | > and the `searchStrategy` property, which is intentionally disallowed.
|
689 |
|
690 | You can also add more root properties outside the `cosmiconfig` property
|
691 | to configure your tools, entirely eliminating the need to look for additional configuration files:
|
692 |
|
693 | ```yaml
|
694 | cosmiconfig:
|
695 | searchPlaces: []
|
696 |
|
697 | prettier:
|
698 | semi: true
|
699 | ```
|
700 |
|
701 | ### Imports
|
702 |
|
703 | Wherever you put your configuration (the package.json file, a root config file or a package-specific config file),
|
704 | you can use the special `$import` key to import another file as a base.
|
705 |
|
706 | For example, you can import from an npm package (in this example, `@foocorp/config`).
|
707 |
|
708 | `.prettierrc.base.yml` in said npm package could define some company-wide defaults:
|
709 |
|
710 | ```yaml
|
711 | printWidth: 120
|
712 | semi: true
|
713 | tabWidth: 2
|
714 | ```
|
715 |
|
716 | And then, the `.prettierrc.yml` file in the project itself would just reference that file,
|
717 | optionally overriding the defaults with project-specific settings:
|
718 |
|
719 | ```yaml
|
720 | $import: node_modules/@foocorp/config/.prettierrc.base.yml
|
721 | # we want more space!
|
722 | printWidth: 200
|
723 | ```
|
724 |
|
725 | It is possible to import multiple base files by specifying an array of paths,
|
726 | which will be processed in declaration order;
|
727 | that means that the last entry will win if there are conflicting properties.
|
728 |
|
729 | It is also possible to import file formats other than the importing format
|
730 | as long as they are supported by the loaders specified by the developer of the tool you're configuring.
|
731 |
|
732 | ```yaml
|
733 | $import: [first.yml, second.json, third.config.js]
|
734 | ```
|
735 |
|
736 | ## Contributing & Development
|
737 |
|
738 | Please note that this project is released with a [Contributor Code of Conduct](CODE_OF_CONDUCT.md). By participating in this project you agree to abide by its terms.
|
739 |
|
740 | And please do participate!
|
741 |
|
742 | [result]: #result
|
743 |
|
744 | [`load()`]: #explorerload
|
745 |
|
746 | [`search()`]: #explorersearch
|
747 |
|
748 | [`clearloadcache()`]: #explorerclearloadcache
|
749 |
|
750 | [`clearsearchcache()`]: #explorerclearsearchcache
|
751 |
|
752 | [`cosmiconfig()`]: #cosmiconfig
|
753 |
|
754 | [`cosmiconfigSync()`]: #cosmiconfigsync
|
755 |
|
756 | [`clearcaches()`]: #explorerclearcaches
|
757 |
|
758 | [`packageprop`]: #packageprop
|
759 |
|
760 | [`cache`]: #cache
|
761 |
|
762 | [`stopdir`]: #stopdir
|
763 |
|
764 | [`searchplaces`]: #searchplaces
|
765 |
|
766 | [`loaders`]: #loaders
|
767 |
|
768 | [`cosmiconfigoptions`]: #cosmiconfigoptions
|
769 |
|
770 | [`explorerSync.search()`]: #explorersyncsearch
|
771 |
|
772 | [`explorerSync.load()`]: #explorersyncload
|
773 |
|
774 | [`explorer.search()`]: #explorersearch
|
775 |
|
776 | [`explorer.load()`]: #explorerload
|
777 |
|
778 | ["Loading JS modules"]: #loading-js-modules
|
779 |
|
780 | [`env-paths`]: https://github.com/sindresorhus/env-paths
|
781 |
|
782 | [search strategies]: #searchstrategy
|