1 | # yargs-parser
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2 |
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3 | [![Build Status](https://travis-ci.org/yargs/yargs-parser.svg)](https://travis-ci.org/yargs/yargs-parser)
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4 | [![NPM version](https://img.shields.io/npm/v/yargs-parser.svg)](https://www.npmjs.com/package/yargs-parser)
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5 | [![Standard Version](https://img.shields.io/badge/release-standard%20version-brightgreen.svg)](https://github.com/conventional-changelog/standard-version)
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6 |
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7 |
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8 | The mighty option parser used by [yargs](https://github.com/yargs/yargs).
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9 |
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10 | visit the [yargs website](http://yargs.js.org/) for more examples, and thorough usage instructions.
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11 |
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12 | <img width="250" src="https://raw.githubusercontent.com/yargs/yargs-parser/master/yargs-logo.png">
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13 |
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14 | ## Example
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15 |
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16 | ```sh
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17 | npm i yargs-parser --save
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18 | ```
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19 |
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20 | ```js
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21 | var argv = require('yargs-parser')(process.argv.slice(2))
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22 | console.log(argv)
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23 | ```
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24 |
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25 | ```sh
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26 | node example.js --foo=33 --bar hello
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27 | { _: [], foo: 33, bar: 'hello' }
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28 | ```
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29 |
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30 | _or parse a string!_
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31 |
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32 | ```js
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33 | var argv = require('yargs-parser')('--foo=99 --bar=33')
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34 | console.log(argv)
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35 | ```
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36 |
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37 | ```sh
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38 | { _: [], foo: 99, bar: 33 }
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39 | ```
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40 |
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41 | Convert an array of mixed types before passing to `yargs-parser`:
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42 |
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43 | ```js
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44 | var parse = require('yargs-parser')
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45 | parse(['-f', 11, '--zoom', 55].join(' ')) // <-- array to string
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46 | parse(['-f', 11, '--zoom', 55].map(String)) // <-- array of strings
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47 | ```
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48 |
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49 | ## API
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50 |
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51 | ### require('yargs-parser')(args, opts={})
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52 |
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53 | Parses command line arguments returning a simple mapping of keys and values.
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54 |
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55 | **expects:**
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56 |
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57 | * `args`: a string or array of strings representing the options to parse.
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58 | * `opts`: provide a set of hints indicating how `args` should be parsed:
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59 | * `opts.alias`: an object representing the set of aliases for a key: `{alias: {foo: ['f']}}`.
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60 | * `opts.array`: indicate that keys should be parsed as an array: `{array: ['foo', 'bar']}`.<br>
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61 | Indicate that keys should be parsed as an array and coerced to booleans / numbers:<br>
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62 | `{array: [{ key: 'foo', boolean: true }, {key: 'bar', number: true}]}`.
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63 | * `opts.boolean`: arguments should be parsed as booleans: `{boolean: ['x', 'y']}`.
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64 | * `opts.coerce`: provide a custom synchronous function that returns a coerced value from the argument provided
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65 | (or throws an error). For arrays the function is called only once for the entire array:<br>
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66 | `{coerce: {foo: function (arg) {return modifiedArg}}}`.
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67 | * `opts.config`: indicate a key that represents a path to a configuration file (this file will be loaded and parsed).
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68 | * `opts.configObjects`: configuration objects to parse, their properties will be set as arguments:<br>
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69 | `{configObjects: [{'x': 5, 'y': 33}, {'z': 44}]}`.
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70 | * `opts.configuration`: provide configuration options to the yargs-parser (see: [configuration](#configuration)).
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71 | * `opts.count`: indicate a key that should be used as a counter, e.g., `-vvv` = `{v: 3}`.
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72 | * `opts.default`: provide default values for keys: `{default: {x: 33, y: 'hello world!'}}`.
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73 | * `opts.envPrefix`: environment variables (`process.env`) with the prefix provided should be parsed.
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74 | * `opts.narg`: specify that a key requires `n` arguments: `{narg: {x: 2}}`.
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75 | * `opts.normalize`: `path.normalize()` will be applied to values set to this key.
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76 | * `opts.number`: keys should be treated as numbers.
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77 | * `opts.string`: keys should be treated as strings (even if they resemble a number `-x 33`).
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78 |
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79 | **returns:**
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80 |
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81 | * `obj`: an object representing the parsed value of `args`
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82 | * `key/value`: key value pairs for each argument and their aliases.
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83 | * `_`: an array representing the positional arguments.
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84 | * [optional] `--`: an array with arguments after the end-of-options flag `--`.
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85 |
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86 | ### require('yargs-parser').detailed(args, opts={})
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87 |
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88 | Parses a command line string, returning detailed information required by the
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89 | yargs engine.
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90 |
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91 | **expects:**
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92 |
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93 | * `args`: a string or array of strings representing options to parse.
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94 | * `opts`: provide a set of hints indicating how `args`, inputs are identical to `require('yargs-parser')(args, opts={})`.
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95 |
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96 | **returns:**
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97 |
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98 | * `argv`: an object representing the parsed value of `args`
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99 | * `key/value`: key value pairs for each argument and their aliases.
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100 | * `_`: an array representing the positional arguments.
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101 | * [optional] `--`: an array with arguments after the end-of-options flag `--`.
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102 | * `error`: populated with an error object if an exception occurred during parsing.
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103 | * `aliases`: the inferred list of aliases built by combining lists in `opts.alias`.
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104 | * `newAliases`: any new aliases added via camel-case expansion:
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105 | * `boolean`: `{ fooBar: true }`
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106 | * `defaulted`: any new argument created by `opts.default`, no aliases included.
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107 | * `boolean`: `{ foo: true }`
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108 | * `configuration`: given by default settings and `opts.configuration`.
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109 |
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110 | <a name="configuration"></a>
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111 |
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112 | ### Configuration
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113 |
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114 | The yargs-parser applies several automated transformations on the keys provided
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115 | in `args`. These features can be turned on and off using the `configuration` field
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116 | of `opts`.
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117 |
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118 | ```js
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119 | var parsed = parser(['--no-dice'], {
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120 | configuration: {
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121 | 'boolean-negation': false
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122 | }
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123 | })
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124 | ```
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125 |
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126 | ### short option groups
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127 |
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128 | * default: `true`.
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129 | * key: `short-option-groups`.
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130 |
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131 | Should a group of short-options be treated as boolean flags?
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132 |
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133 | ```sh
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134 | node example.js -abc
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135 | { _: [], a: true, b: true, c: true }
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136 | ```
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137 |
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138 | _if disabled:_
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139 |
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140 | ```sh
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141 | node example.js -abc
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142 | { _: [], abc: true }
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143 | ```
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144 |
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145 | ### camel-case expansion
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146 |
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147 | * default: `true`.
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148 | * key: `camel-case-expansion`.
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149 |
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150 | Should hyphenated arguments be expanded into camel-case aliases?
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151 |
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152 | ```sh
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153 | node example.js --foo-bar
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154 | { _: [], 'foo-bar': true, fooBar: true }
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155 | ```
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156 |
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157 | _if disabled:_
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158 |
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159 | ```sh
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160 | node example.js --foo-bar
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161 | { _: [], 'foo-bar': true }
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162 | ```
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163 |
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164 | ### dot-notation
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165 |
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166 | * default: `true`
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167 | * key: `dot-notation`
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168 |
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169 | Should keys that contain `.` be treated as objects?
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170 |
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171 | ```sh
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172 | node example.js --foo.bar
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173 | { _: [], foo: { bar: true } }
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174 | ```
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175 |
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176 | _if disabled:_
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177 |
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178 | ```sh
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179 | node example.js --foo.bar
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180 | { _: [], "foo.bar": true }
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181 | ```
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182 |
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183 | ### parse numbers
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184 |
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185 | * default: `true`
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186 | * key: `parse-numbers`
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187 |
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188 | Should keys that look like numbers be treated as such?
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189 |
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190 | ```sh
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191 | node example.js --foo=99.3
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192 | { _: [], foo: 99.3 }
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193 | ```
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194 |
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195 | _if disabled:_
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196 |
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197 | ```sh
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198 | node example.js --foo=99.3
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199 | { _: [], foo: "99.3" }
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200 | ```
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201 |
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202 | ### boolean negation
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203 |
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204 | * default: `true`
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205 | * key: `boolean-negation`
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206 |
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207 | Should variables prefixed with `--no` be treated as negations?
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208 |
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209 | ```sh
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210 | node example.js --no-foo
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211 | { _: [], foo: false }
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212 | ```
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213 |
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214 | _if disabled:_
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215 |
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216 | ```sh
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217 | node example.js --no-foo
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218 | { _: [], "no-foo": true }
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219 | ```
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220 |
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221 | ### combine arrays
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222 |
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223 | * default: `false`
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224 | * key: `combine-arrays`
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225 |
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226 | Should arrays be combined when provided by both command line arguments and
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227 | a configuration file.
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228 |
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229 | ### duplicate arguments array
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230 |
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231 | * default: `true`
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232 | * key: `duplicate-arguments-array`
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233 |
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234 | Should arguments be coerced into an array when duplicated:
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235 |
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236 | ```sh
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237 | node example.js -x 1 -x 2
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238 | { _: [], x: [1, 2] }
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239 | ```
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240 |
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241 | _if disabled:_
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242 |
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243 | ```sh
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244 | node example.js -x 1 -x 2
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245 | { _: [], x: 2 }
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246 | ```
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247 |
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248 | ### flatten duplicate arrays
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249 |
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250 | * default: `true`
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251 | * key: `flatten-duplicate-arrays`
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252 |
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253 | Should array arguments be coerced into a single array when duplicated:
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254 |
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255 | ```sh
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256 | node example.js -x 1 2 -x 3 4
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257 | { _: [], x: [1, 2, 3, 4] }
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258 | ```
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259 |
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260 | _if disabled:_
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261 |
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262 | ```sh
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263 | node example.js -x 1 2 -x 3 4
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264 | { _: [], x: [[1, 2], [3, 4]] }
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265 | ```
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266 |
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267 | ### greedy arrays
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268 |
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269 | * default: `true`
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270 | * key: `greedy-arrays`
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271 |
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272 | Should arrays consume more than one positional argument following their flag.
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273 |
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274 | ```sh
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275 | node example --arr 1 2
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276 | { _[], arr: [1, 2] }
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277 | ```
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278 |
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279 | _if disabled:_
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280 |
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281 | ```sh
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282 | node example --arr 1 2
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283 | { _[2], arr: [1] }
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284 | ```
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285 |
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286 | **Note: in `v18.0.0` we are considering defaulting greedy arrays to `false`.**
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287 |
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288 | ### nargs eats options
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289 |
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290 | * default: `false`
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291 | * key: `nargs-eats-options`
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292 |
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293 | Should nargs consume dash options as well as positional arguments.
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294 |
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295 | ### negation prefix
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296 |
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297 | * default: `no-`
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298 | * key: `negation-prefix`
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299 |
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300 | The prefix to use for negated boolean variables.
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301 |
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302 | ```sh
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303 | node example.js --no-foo
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304 | { _: [], foo: false }
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305 | ```
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306 |
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307 | _if set to `quux`:_
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308 |
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309 | ```sh
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310 | node example.js --quuxfoo
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311 | { _: [], foo: false }
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312 | ```
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313 |
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314 | ### populate --
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315 |
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316 | * default: `false`.
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317 | * key: `populate--`
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318 |
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319 | Should unparsed flags be stored in `--` or `_`.
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320 |
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321 | _If disabled:_
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322 |
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323 | ```sh
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324 | node example.js a -b -- x y
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325 | { _: [ 'a', 'x', 'y' ], b: true }
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326 | ```
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327 |
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328 | _If enabled:_
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329 |
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330 | ```sh
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331 | node example.js a -b -- x y
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332 | { _: [ 'a' ], '--': [ 'x', 'y' ], b: true }
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333 | ```
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334 |
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335 | ### set placeholder key
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336 |
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337 | * default: `false`.
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338 | * key: `set-placeholder-key`.
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339 |
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340 | Should a placeholder be added for keys not set via the corresponding CLI argument?
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341 |
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342 | _If disabled:_
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343 |
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344 | ```sh
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345 | node example.js -a 1 -c 2
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346 | { _: [], a: 1, c: 2 }
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347 | ```
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348 |
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349 | _If enabled:_
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350 |
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351 | ```sh
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352 | node example.js -a 1 -c 2
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353 | { _: [], a: 1, b: undefined, c: 2 }
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354 | ```
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355 |
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356 | ### halt at non-option
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357 |
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358 | * default: `false`.
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359 | * key: `halt-at-non-option`.
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360 |
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361 | Should parsing stop at the first positional argument? This is similar to how e.g. `ssh` parses its command line.
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362 |
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363 | _If disabled:_
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364 |
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365 | ```sh
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366 | node example.js -a run b -x y
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367 | { _: [ 'b' ], a: 'run', x: 'y' }
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368 | ```
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369 |
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370 | _If enabled:_
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371 |
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372 | ```sh
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373 | node example.js -a run b -x y
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374 | { _: [ 'b', '-x', 'y' ], a: 'run' }
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375 | ```
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376 |
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377 | ### strip aliased
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378 |
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379 | * default: `false`
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380 | * key: `strip-aliased`
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381 |
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382 | Should aliases be removed before returning results?
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383 |
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384 | _If disabled:_
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385 |
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386 | ```sh
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387 | node example.js --test-field 1
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388 | { _: [], 'test-field': 1, testField: 1, 'test-alias': 1, testAlias: 1 }
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389 | ```
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390 |
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391 | _If enabled:_
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392 |
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393 | ```sh
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394 | node example.js --test-field 1
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395 | { _: [], 'test-field': 1, testField: 1 }
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396 | ```
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397 |
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398 | ### strip dashed
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399 |
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400 | * default: `false`
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401 | * key: `strip-dashed`
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402 |
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403 | Should dashed keys be removed before returning results? This option has no effect if
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404 | `camel-case-expansion` is disabled.
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405 |
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406 | _If disabled:_
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407 |
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408 | ```sh
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409 | node example.js --test-field 1
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410 | { _: [], 'test-field': 1, testField: 1 }
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411 | ```
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412 |
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413 | _If enabled:_
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414 |
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415 | ```sh
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416 | node example.js --test-field 1
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417 | { _: [], testField: 1 }
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418 | ```
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419 |
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420 | ### unknown options as args
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421 |
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422 | * default: `false`
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423 | * key: `unknown-options-as-args`
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424 |
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425 | Should unknown options be treated like regular arguments? An unknown option is one that is not
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426 | configured in `opts`.
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427 |
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428 | _If disabled_
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429 |
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430 | ```sh
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431 | node example.js --unknown-option --known-option 2 --string-option --unknown-option2
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432 | { _: [], unknownOption: true, knownOption: 2, stringOption: '', unknownOption2: true }
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433 | ```
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434 |
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435 | _If enabled_
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436 |
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437 | ```sh
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438 | node example.js --unknown-option --known-option 2 --string-option --unknown-option2
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439 | { _: ['--unknown-option'], knownOption: 2, stringOption: '--unknown-option2' }
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440 | ```
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441 |
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442 | ## Special Thanks
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443 |
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444 | The yargs project evolves from optimist and minimist. It owes its
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445 | existence to a lot of James Halliday's hard work. Thanks [substack](https://github.com/substack) **beep** **boop** \o/
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446 |
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447 | ## License
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448 |
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449 | ISC
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