/*!
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* type-is
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* Copyright(c) 2014 Jonathan Ong
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* Copyright(c) 2014-2015 Douglas Christopher Wilson
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* MIT Licensed
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*/
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'use strict'
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/**
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* Module dependencies.
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* @private
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*/
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var typer = require('media-typer')
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var mime = require('mime-types')
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/**
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* Module exports.
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* @public
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*/
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module.exports = typeofrequest
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module.exports.is = typeis
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module.exports.hasBody = hasbody
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module.exports.normalize = normalize
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module.exports.match = mimeMatch
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/**
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* Compare a `value` content-type with `types`.
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* Each `type` can be an extension like `html`,
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* a special shortcut like `multipart` or `urlencoded`,
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* or a mime type.
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*
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* If no types match, `false` is returned.
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* Otherwise, the first `type` that matches is returned.
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*
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* @param {String} value
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* @param {Array} types
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* @public
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*/
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function typeis (value, types_) {
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var i
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var types = types_
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// remove parameters and normalize
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var val = tryNormalizeType(value)
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// no type or invalid
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if (!val) {
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return false
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}
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// support flattened arguments
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if (types && !Array.isArray(types)) {
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types = new Array(arguments.length - 1)
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for (i = 0; i < types.length; i++) {
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types[i] = arguments[i + 1]
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}
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}
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// no types, return the content type
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if (!types || !types.length) {
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return val
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}
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var type
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for (i = 0; i < types.length; i++) {
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if (mimeMatch(normalize(type = types[i]), val)) {
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return type[0] === '+' || type.indexOf('*') !== -1
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? val
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: type
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}
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}
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// no matches
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return false
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}
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/**
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* Check if a request has a request body.
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* A request with a body __must__ either have `transfer-encoding`
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* or `content-length` headers set.
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* http://www.w3.org/Protocols/rfc2616/rfc2616-sec4.html#sec4.3
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*
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* @param {Object} request
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* @return {Boolean}
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* @public
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*/
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function hasbody (req) {
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return req.headers['transfer-encoding'] !== undefined ||
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!isNaN(req.headers['content-length'])
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}
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/**
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* Check if the incoming request contains the "Content-Type"
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* header field, and it contains any of the give mime `type`s.
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* If there is no request body, `null` is returned.
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* If there is no content type, `false` is returned.
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* Otherwise, it returns the first `type` that matches.
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*
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* Examples:
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*
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* // With Content-Type: text/html; charset=utf-8
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* this.is('html'); // => 'html'
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* this.is('text/html'); // => 'text/html'
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* this.is('text/*', 'application/json'); // => 'text/html'
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*
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* // When Content-Type is application/json
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* this.is('json', 'urlencoded'); // => 'json'
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* this.is('application/json'); // => 'application/json'
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* this.is('html', 'application/*'); // => 'application/json'
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*
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* this.is('html'); // => false
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*
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* @param {String|Array} types...
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* @return {String|false|null}
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* @public
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*/
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function typeofrequest (req, types_) {
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var types = types_
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// no body
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if (!hasbody(req)) {
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return null
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}
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// support flattened arguments
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if (arguments.length > 2) {
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types = new Array(arguments.length - 1)
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for (var i = 0; i < types.length; i++) {
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types[i] = arguments[i + 1]
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}
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}
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// request content type
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var value = req.headers['content-type']
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return typeis(value, types)
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}
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/**
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* Normalize a mime type.
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* If it's a shorthand, expand it to a valid mime type.
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*
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* In general, you probably want:
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*
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* var type = is(req, ['urlencoded', 'json', 'multipart']);
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*
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* Then use the appropriate body parsers.
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* These three are the most common request body types
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* and are thus ensured to work.
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*
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* @param {String} type
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* @private
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*/
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function normalize (type) {
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if (typeof type !== 'string') {
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// invalid type
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return false
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}
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switch (type) {
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case 'urlencoded':
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return 'application/x-www-form-urlencoded'
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case 'multipart':
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return 'multipart/*'
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}
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if (type[0] === '+') {
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// "+json" -> "*/*+json" expando
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return '*/*' + type
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}
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return type.indexOf('/') === -1
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? mime.lookup(type)
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: type
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}
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/**
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* Check if `expected` mime type
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* matches `actual` mime type with
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* wildcard and +suffix support.
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*
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* @param {String} expected
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* @param {String} actual
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* @return {Boolean}
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* @private
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*/
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function mimeMatch (expected, actual) {
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// invalid type
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if (expected === false) {
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return false
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}
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// split types
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var actualParts = actual.split('/')
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var expectedParts = expected.split('/')
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// invalid format
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if (actualParts.length !== 2 || expectedParts.length !== 2) {
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return false
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}
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// validate type
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if (expectedParts[0] !== '*' && expectedParts[0] !== actualParts[0]) {
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return false
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}
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// validate suffix wildcard
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if (expectedParts[1].substr(0, 2) === '*+') {
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return expectedParts[1].length <= actualParts[1].length + 1 &&
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expectedParts[1].substr(1) === actualParts[1].substr(1 - expectedParts[1].length)
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}
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// validate subtype
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if (expectedParts[1] !== '*' && expectedParts[1] !== actualParts[1]) {
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return false
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}
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return true
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}
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/**
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* Normalize a type and remove parameters.
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*
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* @param {string} value
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* @return {string}
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* @private
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*/
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function normalizeType (value) {
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// parse the type
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var type = typer.parse(value)
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// remove the parameters
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type.parameters = undefined
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// reformat it
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return typer.format(type)
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}
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/**
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* Try to normalize a type and remove parameters.
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*
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* @param {string} value
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* @return {string}
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* @private
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*/
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function tryNormalizeType (value) {
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if (!value) {
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return null
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}
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try {
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return normalizeType(value)
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} catch (err) {
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return null
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}
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}
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