1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
|
var Preloader = /** @constructor */ function() {
var DOWNLOAD_ATTEMPTS_MAX = 4;
var progressFunc = null;
var lastProgress = { loaded: 0, total: 0 };
var loadingFiles = {};
this.preloadedFiles = [];
function loadXHR(resolve, reject, file, tracker) {
var xhr = new XMLHttpRequest;
xhr.open('GET', file);
if (!file.endsWith('.js')) {
xhr.responseType = 'arraybuffer';
}
['loadstart', 'progress', 'load', 'error', 'abort'].forEach(function(ev) {
xhr.addEventListener(ev, onXHREvent.bind(xhr, resolve, reject, file, tracker));
});
xhr.send();
}
function onXHREvent(resolve, reject, file, tracker, ev) {
if (this.status >= 400) {
if (this.status < 500 || ++tracker[file].attempts >= DOWNLOAD_ATTEMPTS_MAX) {
reject(new Error("Failed loading file '" + file + "': " + this.statusText));
this.abort();
return;
} else {
setTimeout(loadXHR.bind(null, resolve, reject, file, tracker), 1000);
}
}
switch (ev.type) {
case 'loadstart':
if (tracker[file] === undefined) {
tracker[file] = {
total: ev.total,
loaded: ev.loaded,
attempts: 0,
final: false,
};
}
break;
case 'progress':
tracker[file].loaded = ev.loaded;
tracker[file].total = ev.total;
break;
case 'load':
tracker[file].final = true;
resolve(this);
break;
case 'error':
if (++tracker[file].attempts >= DOWNLOAD_ATTEMPTS_MAX) {
tracker[file].final = true;
reject(new Error("Failed loading file '" + file + "'"));
} else {
setTimeout(loadXHR.bind(null, resolve, reject, file, tracker), 1000);
}
break;
case 'abort':
tracker[file].final = true;
reject(new Error("Loading file '" + file + "' was aborted."));
break;
}
}
this.loadPromise = function(file) {
return new Promise(function(resolve, reject) {
loadXHR(resolve, reject, file, loadingFiles);
});
}
this.preload = function(pathOrBuffer, destPath) {
if (pathOrBuffer instanceof ArrayBuffer) {
pathOrBuffer = new Uint8Array(pathOrBuffer);
} else if (ArrayBuffer.isView(pathOrBuffer)) {
pathOrBuffer = new Uint8Array(pathOrBuffer.buffer);
}
if (pathOrBuffer instanceof Uint8Array) {
this.preloadedFiles.push({
path: destPath,
buffer: pathOrBuffer
});
return Promise.resolve();
} else if (typeof pathOrBuffer === 'string') {
var me = this;
return this.loadPromise(pathOrBuffer).then(function(xhr) {
me.preloadedFiles.push({
path: destPath || pathOrBuffer,
buffer: xhr.response
});
return Promise.resolve();
});
} else {
throw Promise.reject("Invalid object for preloading");
}
};
var animateProgress = function() {
var loaded = 0;
var total = 0;
var totalIsValid = true;
var progressIsFinal = true;
Object.keys(loadingFiles).forEach(function(file) {
const stat = loadingFiles[file];
if (!stat.final) {
progressIsFinal = false;
}
if (!totalIsValid || stat.total === 0) {
totalIsValid = false;
total = 0;
} else {
total += stat.total;
}
loaded += stat.loaded;
});
if (loaded !== lastProgress.loaded || total !== lastProgress.total) {
lastProgress.loaded = loaded;
lastProgress.total = total;
if (typeof progressFunc === 'function')
progressFunc(loaded, total);
}
if (!progressIsFinal)
requestAnimationFrame(animateProgress);
}
this.animateProgress = animateProgress; // Also exposed to start it.
this.setProgressFunc = function(callback) {
progressFunc = callback;
}
};
|