1 | var path = require('path');
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2 | var fs = require('fs');
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3 | var utils = require('./utils');
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4 | var del = require('./del');
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5 | var writeJSON = utils.writeJSON;
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6 |
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7 | var cache = {
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8 | /**
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9 | * Load a cache identified by the given Id. If the element does not exists, then initialize an empty
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10 | * cache storage. If specified `cacheDir` will be used as the directory to persist the data to. If omitted
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11 | * then the cache module directory `./cache` will be used instead
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12 | *
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13 | * @method load
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14 | * @param docId {String} the id of the cache, would also be used as the name of the file cache
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15 | * @param [cacheDir] {String} directory for the cache entry
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16 | */
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17 | load: function (docId, cacheDir) {
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18 | var me = this;
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19 |
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20 | me._visited = {};
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21 | me._persisted = {};
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22 | me._pathToFile = cacheDir ? path.resolve(cacheDir, docId) : path.resolve(__dirname, '../.cache/', docId);
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23 |
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24 | if (fs.existsSync(me._pathToFile)) {
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25 | me._persisted = utils.tryParse(me._pathToFile, {});
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26 | }
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27 | },
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28 |
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29 | /**
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30 | * Load the cache from the provided file
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31 | * @method loadFile
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32 | * @param {String} pathToFile the path to the file containing the info for the cache
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33 | */
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34 | loadFile: function (pathToFile) {
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35 | var me = this;
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36 | var dir = path.dirname(pathToFile);
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37 | var fName = path.basename(pathToFile);
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38 |
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39 | me.load(fName, dir);
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40 | },
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41 |
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42 | /**
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43 | * Returns the entire persisted object
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44 | * @method all
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45 | * @returns {*}
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46 | */
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47 | all: function () {
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48 | return this._persisted;
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49 | },
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50 |
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51 | keys: function () {
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52 | return Object.keys(this._persisted);
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53 | },
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54 | /**
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55 | * sets a key to a given value
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56 | * @method setKey
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57 | * @param key {string} the key to set
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58 | * @param value {object} the value of the key. Could be any object that can be serialized with JSON.stringify
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59 | */
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60 | setKey: function (key, value) {
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61 | this._visited[key] = true;
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62 | this._persisted[key] = value;
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63 | },
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64 | /**
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65 | * remove a given key from the cache
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66 | * @method removeKey
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67 | * @param key {String} the key to remove from the object
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68 | */
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69 | removeKey: function (key) {
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70 | delete this._visited[key]; // esfmt-ignore-line
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71 | delete this._persisted[key]; // esfmt-ignore-line
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72 | },
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73 | /**
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74 | * Return the value of the provided key
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75 | * @method getKey
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76 | * @param key {String} the name of the key to retrieve
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77 | * @returns {*} the value from the key
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78 | */
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79 | getKey: function (key) {
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80 | this._visited[key] = true;
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81 | return this._persisted[key];
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82 | },
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83 |
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84 | /**
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85 | * Remove keys that were not accessed/set since the
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86 | * last time the `prune` method was called.
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87 | * @method _prune
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88 | * @private
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89 | */
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90 | _prune: function () {
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91 | var me = this;
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92 | var obj = {};
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93 |
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94 | var keys = Object.keys(me._visited);
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95 |
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96 | // no keys visited for either get or set value
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97 | if (keys.length === 0) {
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98 | return;
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99 | }
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100 |
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101 | keys.forEach(function (key) {
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102 | obj[key] = me._persisted[key];
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103 | });
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104 |
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105 | me._visited = {};
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106 | me._persisted = obj;
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107 | },
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108 |
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109 | /**
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110 | * Save the state of the cache identified by the docId to disk
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111 | * as a JSON structure
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112 | * @param [noPrune=false] {Boolean} whether to remove from cache the non visited files
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113 | * @method save
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114 | */
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115 | save: function (noPrune) {
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116 | var me = this;
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117 |
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118 | !noPrune && me._prune();
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119 | writeJSON(me._pathToFile, me._persisted);
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120 | },
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121 |
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122 | /**
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123 | * remove the file where the cache is persisted
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124 | * @method removeCacheFile
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125 | * @return {Boolean} true or false if the file was successfully deleted
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126 | */
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127 | removeCacheFile: function () {
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128 | return del(this._pathToFile);
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129 | },
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130 | /**
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131 | * Destroy the file cache and cache content.
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132 | * @method destroy
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133 | */
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134 | destroy: function () {
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135 | var me = this;
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136 | me._visited = {};
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137 | me._persisted = {};
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138 |
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139 | me.removeCacheFile();
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140 | },
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141 | };
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142 |
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143 | module.exports = {
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144 | /**
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145 | * Alias for create. Should be considered depreacted. Will be removed in next releases
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146 | *
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147 | * @method load
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148 | * @param docId {String} the id of the cache, would also be used as the name of the file cache
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149 | * @param [cacheDir] {String} directory for the cache entry
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150 | * @returns {cache} cache instance
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151 | */
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152 | load: function (docId, cacheDir) {
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153 | return this.create(docId, cacheDir);
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154 | },
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155 |
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156 | /**
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157 | * Load a cache identified by the given Id. If the element does not exists, then initialize an empty
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158 | * cache storage.
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159 | *
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160 | * @method create
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161 | * @param docId {String} the id of the cache, would also be used as the name of the file cache
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162 | * @param [cacheDir] {String} directory for the cache entry
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163 | * @returns {cache} cache instance
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164 | */
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165 | create: function (docId, cacheDir) {
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166 | var obj = Object.create(cache);
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167 | obj.load(docId, cacheDir);
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168 | return obj;
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169 | },
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170 |
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171 | createFromFile: function (filePath) {
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172 | var obj = Object.create(cache);
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173 | obj.loadFile(filePath);
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174 | return obj;
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175 | },
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176 | /**
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177 | * Clear the cache identified by the given id. Caches stored in a different cache directory can be deleted directly
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178 | *
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179 | * @method clearCache
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180 | * @param docId {String} the id of the cache, would also be used as the name of the file cache
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181 | * @param cacheDir {String} the directory where the cache file was written
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182 | * @returns {Boolean} true if the cache folder was deleted. False otherwise
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183 | */
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184 | clearCacheById: function (docId, cacheDir) {
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185 | var filePath = cacheDir ? path.resolve(cacheDir, docId) : path.resolve(__dirname, '../.cache/', docId);
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186 | return del(filePath);
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187 | },
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188 | /**
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189 | * Remove all cache stored in the cache directory
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190 | * @method clearAll
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191 | * @returns {Boolean} true if the cache folder was deleted. False otherwise
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192 | */
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193 | clearAll: function (cacheDir) {
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194 | var filePath = cacheDir ? path.resolve(cacheDir) : path.resolve(__dirname, '../.cache/');
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195 | return del(filePath);
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196 | },
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197 | };
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