1 | # type-is
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2 |
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3 | [![NPM Version][npm-version-image]][npm-url]
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4 | [![NPM Downloads][npm-downloads-image]][npm-url]
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5 | [![Node.js Version][node-version-image]][node-version-url]
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6 | [![Build Status][travis-image]][travis-url]
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7 | [![Test Coverage][coveralls-image]][coveralls-url]
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8 |
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9 | Infer the content-type of a request.
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10 |
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11 | ### Install
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12 |
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13 | This is a [Node.js](https://nodejs.org/en/) module available through the
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14 | [npm registry](https://www.npmjs.com/). Installation is done using the
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15 | [`npm install` command](https://docs.npmjs.com/getting-started/installing-npm-packages-locally):
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16 |
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17 | ```sh
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18 | $ npm install type-is
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19 | ```
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20 |
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21 | ## API
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22 |
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23 | ```js
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24 | var http = require('http')
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25 | var typeis = require('type-is')
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26 |
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27 | http.createServer(function (req, res) {
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28 | var istext = typeis(req, ['text/*'])
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29 | res.end('you ' + (istext ? 'sent' : 'did not send') + ' me text')
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30 | })
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31 | ```
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32 |
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33 | ### typeis(request, types)
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34 |
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35 | Checks if the `request` is one of the `types`. If the request has no body,
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36 | even if there is a `Content-Type` header, then `null` is returned. If the
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37 | `Content-Type` header is invalid or does not matches any of the `types`, then
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38 | `false` is returned. Otherwise, a string of the type that matched is returned.
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39 |
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40 | The `request` argument is expected to be a Node.js HTTP request. The `types`
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41 | argument is an array of type strings.
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42 |
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43 | Each type in the `types` array can be one of the following:
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44 |
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45 | - A file extension name such as `json`. This name will be returned if matched.
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46 | - A mime type such as `application/json`.
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47 | - A mime type with a wildcard such as `*/*` or `*/json` or `application/*`.
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48 | The full mime type will be returned if matched.
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49 | - A suffix such as `+json`. This can be combined with a wildcard such as
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50 | `*/vnd+json` or `application/*+json`. The full mime type will be returned
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51 | if matched.
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52 |
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53 | Some examples to illustrate the inputs and returned value:
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54 |
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55 | <!-- eslint-disable no-undef -->
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56 |
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57 | ```js
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58 | // req.headers.content-type = 'application/json'
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59 |
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60 | typeis(req, ['json']) // => 'json'
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61 | typeis(req, ['html', 'json']) // => 'json'
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62 | typeis(req, ['application/*']) // => 'application/json'
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63 | typeis(req, ['application/json']) // => 'application/json'
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64 |
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65 | typeis(req, ['html']) // => false
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66 | ```
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67 |
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68 | ### typeis.hasBody(request)
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69 |
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70 | Returns a Boolean if the given `request` has a body, regardless of the
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71 | `Content-Type` header.
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72 |
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73 | Having a body has no relation to how large the body is (it may be 0 bytes).
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74 | This is similar to how file existence works. If a body does exist, then this
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75 | indicates that there is data to read from the Node.js request stream.
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76 |
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77 | <!-- eslint-disable no-undef -->
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78 |
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79 | ```js
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80 | if (typeis.hasBody(req)) {
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81 | // read the body, since there is one
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82 |
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83 | req.on('data', function (chunk) {
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84 | // ...
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85 | })
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86 | }
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87 | ```
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88 |
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89 | ### typeis.is(mediaType, types)
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90 |
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91 | Checks if the `mediaType` is one of the `types`. If the `mediaType` is invalid
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92 | or does not matches any of the `types`, then `false` is returned. Otherwise, a
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93 | string of the type that matched is returned.
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94 |
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95 | The `mediaType` argument is expected to be a
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96 | [media type](https://tools.ietf.org/html/rfc6838) string. The `types` argument
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97 | is an array of type strings.
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98 |
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99 | Each type in the `types` array can be one of the following:
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100 |
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101 | - A file extension name such as `json`. This name will be returned if matched.
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102 | - A mime type such as `application/json`.
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103 | - A mime type with a wildcard such as `*/*` or `*/json` or `application/*`.
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104 | The full mime type will be returned if matched.
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105 | - A suffix such as `+json`. This can be combined with a wildcard such as
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106 | `*/vnd+json` or `application/*+json`. The full mime type will be returned
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107 | if matched.
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108 |
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109 | Some examples to illustrate the inputs and returned value:
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110 |
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111 | <!-- eslint-disable no-undef -->
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112 |
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113 | ```js
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114 | var mediaType = 'application/json'
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115 |
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116 | typeis.is(mediaType, ['json']) // => 'json'
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117 | typeis.is(mediaType, ['html', 'json']) // => 'json'
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118 | typeis.is(mediaType, ['application/*']) // => 'application/json'
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119 | typeis.is(mediaType, ['application/json']) // => 'application/json'
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120 |
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121 | typeis.is(mediaType, ['html']) // => false
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122 | ```
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123 |
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124 | ## Examples
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125 |
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126 | ### Example body parser
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127 |
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128 | ```js
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129 | var express = require('express')
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130 | var typeis = require('type-is')
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131 |
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132 | var app = express()
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133 |
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134 | app.use(function bodyParser (req, res, next) {
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135 | if (!typeis.hasBody(req)) {
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136 | return next()
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137 | }
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138 |
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139 | switch (typeis(req, ['urlencoded', 'json', 'multipart'])) {
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140 | case 'urlencoded':
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141 | // parse urlencoded body
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142 | throw new Error('implement urlencoded body parsing')
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143 | case 'json':
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144 | // parse json body
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145 | throw new Error('implement json body parsing')
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146 | case 'multipart':
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147 | // parse multipart body
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148 | throw new Error('implement multipart body parsing')
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149 | default:
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150 | // 415 error code
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151 | res.statusCode = 415
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152 | res.end()
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153 | break
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154 | }
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155 | })
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156 | ```
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157 |
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158 | ## License
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159 |
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160 | [MIT](LICENSE)
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161 |
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162 | [coveralls-image]: https://badgen.net/coveralls/c/github/jshttp/type-is/master
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163 | [coveralls-url]: https://coveralls.io/r/jshttp/type-is?branch=master
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164 | [node-version-image]: https://badgen.net/npm/node/type-is
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165 | [node-version-url]: https://nodejs.org/en/download
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166 | [npm-downloads-image]: https://badgen.net/npm/dm/type-is
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167 | [npm-url]: https://npmjs.org/package/type-is
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168 | [npm-version-image]: https://badgen.net/npm/v/type-is
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169 | [travis-image]: https://badgen.net/travis/jshttp/type-is/master
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170 | [travis-url]: https://travis-ci.org/jshttp/type-is
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