source: trip-planner-front/node_modules/on-headers/index.js@ 6a3a178

Last change on this file since 6a3a178 was 6a3a178, checked in by Ema <ema_spirova@…>, 3 years ago

initial commit

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1/*!
2 * on-headers
3 * Copyright(c) 2014 Douglas Christopher Wilson
4 * MIT Licensed
5 */
6
7'use strict'
8
9/**
10 * Module exports.
11 * @public
12 */
13
14module.exports = onHeaders
15
16/**
17 * Create a replacement writeHead method.
18 *
19 * @param {function} prevWriteHead
20 * @param {function} listener
21 * @private
22 */
23
24function createWriteHead (prevWriteHead, listener) {
25 var fired = false
26
27 // return function with core name and argument list
28 return function writeHead (statusCode) {
29 // set headers from arguments
30 var args = setWriteHeadHeaders.apply(this, arguments)
31
32 // fire listener
33 if (!fired) {
34 fired = true
35 listener.call(this)
36
37 // pass-along an updated status code
38 if (typeof args[0] === 'number' && this.statusCode !== args[0]) {
39 args[0] = this.statusCode
40 args.length = 1
41 }
42 }
43
44 return prevWriteHead.apply(this, args)
45 }
46}
47
48/**
49 * Execute a listener when a response is about to write headers.
50 *
51 * @param {object} res
52 * @return {function} listener
53 * @public
54 */
55
56function onHeaders (res, listener) {
57 if (!res) {
58 throw new TypeError('argument res is required')
59 }
60
61 if (typeof listener !== 'function') {
62 throw new TypeError('argument listener must be a function')
63 }
64
65 res.writeHead = createWriteHead(res.writeHead, listener)
66}
67
68/**
69 * Set headers contained in array on the response object.
70 *
71 * @param {object} res
72 * @param {array} headers
73 * @private
74 */
75
76function setHeadersFromArray (res, headers) {
77 for (var i = 0; i < headers.length; i++) {
78 res.setHeader(headers[i][0], headers[i][1])
79 }
80}
81
82/**
83 * Set headers contained in object on the response object.
84 *
85 * @param {object} res
86 * @param {object} headers
87 * @private
88 */
89
90function setHeadersFromObject (res, headers) {
91 var keys = Object.keys(headers)
92 for (var i = 0; i < keys.length; i++) {
93 var k = keys[i]
94 if (k) res.setHeader(k, headers[k])
95 }
96}
97
98/**
99 * Set headers and other properties on the response object.
100 *
101 * @param {number} statusCode
102 * @private
103 */
104
105function setWriteHeadHeaders (statusCode) {
106 var length = arguments.length
107 var headerIndex = length > 1 && typeof arguments[1] === 'string'
108 ? 2
109 : 1
110
111 var headers = length >= headerIndex + 1
112 ? arguments[headerIndex]
113 : undefined
114
115 this.statusCode = statusCode
116
117 if (Array.isArray(headers)) {
118 // handle array case
119 setHeadersFromArray(this, headers)
120 } else if (headers) {
121 // handle object case
122 setHeadersFromObject(this, headers)
123 }
124
125 // copy leading arguments
126 var args = new Array(Math.min(length, headerIndex))
127 for (var i = 0; i < args.length; i++) {
128 args[i] = arguments[i]
129 }
130
131 return args
132}
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