1 | /*!
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2 | * type-is
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3 | * Copyright(c) 2014 Jonathan Ong
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4 | * Copyright(c) 2014-2015 Douglas Christopher Wilson
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5 | * MIT Licensed
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6 | */
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7 |
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8 | 'use strict'
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9 |
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10 | /**
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11 | * Module dependencies.
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12 | * @private
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13 | */
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14 |
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15 | var typer = require('media-typer')
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16 | var mime = require('mime-types')
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17 |
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18 | /**
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19 | * Module exports.
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20 | * @public
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21 | */
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22 |
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23 | module.exports = typeofrequest
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24 | module.exports.is = typeis
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25 | module.exports.hasBody = hasbody
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26 | module.exports.normalize = normalize
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27 | module.exports.match = mimeMatch
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28 |
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29 | /**
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30 | * Compare a `value` content-type with `types`.
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31 | * Each `type` can be an extension like `html`,
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32 | * a special shortcut like `multipart` or `urlencoded`,
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33 | * or a mime type.
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34 | *
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35 | * If no types match, `false` is returned.
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36 | * Otherwise, the first `type` that matches is returned.
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37 | *
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38 | * @param {String} value
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39 | * @param {Array} types
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40 | * @public
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41 | */
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42 |
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43 | function typeis (value, types_) {
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44 | var i
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45 | var types = types_
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46 |
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47 | // remove parameters and normalize
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48 | var val = tryNormalizeType(value)
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49 |
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50 | // no type or invalid
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51 | if (!val) {
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52 | return false
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53 | }
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54 |
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55 | // support flattened arguments
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56 | if (types && !Array.isArray(types)) {
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57 | types = new Array(arguments.length - 1)
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58 | for (i = 0; i < types.length; i++) {
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59 | types[i] = arguments[i + 1]
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60 | }
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61 | }
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62 |
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63 | // no types, return the content type
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64 | if (!types || !types.length) {
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65 | return val
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66 | }
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67 |
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68 | var type
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69 | for (i = 0; i < types.length; i++) {
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70 | if (mimeMatch(normalize(type = types[i]), val)) {
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71 | return type[0] === '+' || type.indexOf('*') !== -1
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72 | ? val
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73 | : type
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74 | }
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75 | }
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76 |
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77 | // no matches
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78 | return false
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79 | }
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80 |
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81 | /**
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82 | * Check if a request has a request body.
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83 | * A request with a body __must__ either have `transfer-encoding`
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84 | * or `content-length` headers set.
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85 | * http://www.w3.org/Protocols/rfc2616/rfc2616-sec4.html#sec4.3
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86 | *
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87 | * @param {Object} request
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88 | * @return {Boolean}
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89 | * @public
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90 | */
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91 |
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92 | function hasbody (req) {
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93 | return req.headers['transfer-encoding'] !== undefined ||
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94 | !isNaN(req.headers['content-length'])
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95 | }
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96 |
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97 | /**
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98 | * Check if the incoming request contains the "Content-Type"
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99 | * header field, and it contains any of the give mime `type`s.
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100 | * If there is no request body, `null` is returned.
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101 | * If there is no content type, `false` is returned.
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102 | * Otherwise, it returns the first `type` that matches.
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103 | *
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104 | * Examples:
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105 | *
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106 | * // With Content-Type: text/html; charset=utf-8
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107 | * this.is('html'); // => 'html'
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108 | * this.is('text/html'); // => 'text/html'
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109 | * this.is('text/*', 'application/json'); // => 'text/html'
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110 | *
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111 | * // When Content-Type is application/json
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112 | * this.is('json', 'urlencoded'); // => 'json'
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113 | * this.is('application/json'); // => 'application/json'
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114 | * this.is('html', 'application/*'); // => 'application/json'
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115 | *
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116 | * this.is('html'); // => false
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117 | *
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118 | * @param {String|Array} types...
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119 | * @return {String|false|null}
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120 | * @public
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121 | */
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122 |
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123 | function typeofrequest (req, types_) {
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124 | var types = types_
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125 |
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126 | // no body
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127 | if (!hasbody(req)) {
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128 | return null
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129 | }
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130 |
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131 | // support flattened arguments
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132 | if (arguments.length > 2) {
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133 | types = new Array(arguments.length - 1)
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134 | for (var i = 0; i < types.length; i++) {
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135 | types[i] = arguments[i + 1]
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136 | }
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137 | }
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138 |
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139 | // request content type
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140 | var value = req.headers['content-type']
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141 |
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142 | return typeis(value, types)
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143 | }
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144 |
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145 | /**
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146 | * Normalize a mime type.
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147 | * If it's a shorthand, expand it to a valid mime type.
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148 | *
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149 | * In general, you probably want:
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150 | *
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151 | * var type = is(req, ['urlencoded', 'json', 'multipart']);
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152 | *
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153 | * Then use the appropriate body parsers.
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154 | * These three are the most common request body types
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155 | * and are thus ensured to work.
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156 | *
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157 | * @param {String} type
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158 | * @private
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159 | */
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160 |
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161 | function normalize (type) {
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162 | if (typeof type !== 'string') {
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163 | // invalid type
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164 | return false
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165 | }
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166 |
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167 | switch (type) {
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168 | case 'urlencoded':
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169 | return 'application/x-www-form-urlencoded'
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170 | case 'multipart':
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171 | return 'multipart/*'
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172 | }
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173 |
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174 | if (type[0] === '+') {
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175 | // "+json" -> "*/*+json" expando
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176 | return '*/*' + type
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177 | }
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178 |
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179 | return type.indexOf('/') === -1
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180 | ? mime.lookup(type)
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181 | : type
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182 | }
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183 |
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184 | /**
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185 | * Check if `expected` mime type
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186 | * matches `actual` mime type with
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187 | * wildcard and +suffix support.
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188 | *
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189 | * @param {String} expected
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190 | * @param {String} actual
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191 | * @return {Boolean}
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192 | * @private
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193 | */
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194 |
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195 | function mimeMatch (expected, actual) {
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196 | // invalid type
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197 | if (expected === false) {
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198 | return false
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199 | }
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200 |
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201 | // split types
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202 | var actualParts = actual.split('/')
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203 | var expectedParts = expected.split('/')
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204 |
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205 | // invalid format
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206 | if (actualParts.length !== 2 || expectedParts.length !== 2) {
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207 | return false
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208 | }
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209 |
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210 | // validate type
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211 | if (expectedParts[0] !== '*' && expectedParts[0] !== actualParts[0]) {
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212 | return false
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213 | }
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214 |
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215 | // validate suffix wildcard
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216 | if (expectedParts[1].substr(0, 2) === '*+') {
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217 | return expectedParts[1].length <= actualParts[1].length + 1 &&
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218 | expectedParts[1].substr(1) === actualParts[1].substr(1 - expectedParts[1].length)
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219 | }
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220 |
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221 | // validate subtype
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222 | if (expectedParts[1] !== '*' && expectedParts[1] !== actualParts[1]) {
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223 | return false
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224 | }
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225 |
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226 | return true
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227 | }
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228 |
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229 | /**
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230 | * Normalize a type and remove parameters.
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231 | *
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232 | * @param {string} value
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233 | * @return {string}
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234 | * @private
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235 | */
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236 |
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237 | function normalizeType (value) {
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238 | // parse the type
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239 | var type = typer.parse(value)
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240 |
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241 | // remove the parameters
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242 | type.parameters = undefined
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243 |
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244 | // reformat it
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245 | return typer.format(type)
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246 | }
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247 |
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248 | /**
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249 | * Try to normalize a type and remove parameters.
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250 | *
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251 | * @param {string} value
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252 | * @return {string}
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253 | * @private
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254 | */
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255 |
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256 | function tryNormalizeType (value) {
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257 | if (!value) {
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258 | return null
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259 | }
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260 |
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261 | try {
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262 | return normalizeType(value)
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263 | } catch (err) {
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264 | return null
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265 | }
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266 | }
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