source: trip-planner-front/node_modules/through/index.js@ fa375fe

Last change on this file since fa375fe was 6a3a178, checked in by Ema <ema_spirova@…>, 3 years ago

initial commit

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1var Stream = require('stream')
2
3// through
4//
5// a stream that does nothing but re-emit the input.
6// useful for aggregating a series of changing but not ending streams into one stream)
7
8exports = module.exports = through
9through.through = through
10
11//create a readable writable stream.
12
13function through (write, end, opts) {
14 write = write || function (data) { this.queue(data) }
15 end = end || function () { this.queue(null) }
16
17 var ended = false, destroyed = false, buffer = [], _ended = false
18 var stream = new Stream()
19 stream.readable = stream.writable = true
20 stream.paused = false
21
22// stream.autoPause = !(opts && opts.autoPause === false)
23 stream.autoDestroy = !(opts && opts.autoDestroy === false)
24
25 stream.write = function (data) {
26 write.call(this, data)
27 return !stream.paused
28 }
29
30 function drain() {
31 while(buffer.length && !stream.paused) {
32 var data = buffer.shift()
33 if(null === data)
34 return stream.emit('end')
35 else
36 stream.emit('data', data)
37 }
38 }
39
40 stream.queue = stream.push = function (data) {
41// console.error(ended)
42 if(_ended) return stream
43 if(data === null) _ended = true
44 buffer.push(data)
45 drain()
46 return stream
47 }
48
49 //this will be registered as the first 'end' listener
50 //must call destroy next tick, to make sure we're after any
51 //stream piped from here.
52 //this is only a problem if end is not emitted synchronously.
53 //a nicer way to do this is to make sure this is the last listener for 'end'
54
55 stream.on('end', function () {
56 stream.readable = false
57 if(!stream.writable && stream.autoDestroy)
58 process.nextTick(function () {
59 stream.destroy()
60 })
61 })
62
63 function _end () {
64 stream.writable = false
65 end.call(stream)
66 if(!stream.readable && stream.autoDestroy)
67 stream.destroy()
68 }
69
70 stream.end = function (data) {
71 if(ended) return
72 ended = true
73 if(arguments.length) stream.write(data)
74 _end() // will emit or queue
75 return stream
76 }
77
78 stream.destroy = function () {
79 if(destroyed) return
80 destroyed = true
81 ended = true
82 buffer.length = 0
83 stream.writable = stream.readable = false
84 stream.emit('close')
85 return stream
86 }
87
88 stream.pause = function () {
89 if(stream.paused) return
90 stream.paused = true
91 return stream
92 }
93
94 stream.resume = function () {
95 if(stream.paused) {
96 stream.paused = false
97 stream.emit('resume')
98 }
99 drain()
100 //may have become paused again,
101 //as drain emits 'data'.
102 if(!stream.paused)
103 stream.emit('drain')
104 return stream
105 }
106 return stream
107}
108
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