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var Preloader = /** @constructor */ function() { // eslint-disable-line no-unused-vars
const loadXHR = function(resolve, reject, file, tracker, attempts) {
const xhr = new XMLHttpRequest();
tracker[file] = {
total: 0,
loaded: 0,
final: false,
};
xhr.onerror = function() {
if (attempts <= 1) {
reject(new Error("Failed loading file '" + file + "'"));
} else {
setTimeout(function () {
loadXHR(resolve, reject, file, tracker, attempts - 1);
}, 1000);
}
};
xhr.onabort = function() {
tracker[file].final = true;
reject(new Error("Loading file '" + file + "' was aborted."));
};
xhr.onloadstart = function(ev) {
tracker[file].total = ev.total;
tracker[file].loaded = ev.loaded;
};
xhr.onprogress = function(ev) {
tracker[file].loaded = ev.loaded;
tracker[file].total = ev.total;
};
xhr.onload = function() {
if (xhr.status >= 400) {
if (xhr.status < 500 || attempts <= 1) {
reject(new Error("Failed loading file '" + file + "': " + xhr.statusText));
xhr.abort();
} else {
setTimeout(function () {
loadXHR(resolve, reject, file, tracker, attempts - 1);
}, 1000);
}
} else {
tracker[file].final = true;
resolve(xhr);
}
};
// Make request.
xhr.open('GET', file);
if (!file.endsWith('.js')) {
xhr.responseType = 'arraybuffer';
}
xhr.send();
};
const DOWNLOAD_ATTEMPTS_MAX = 4;
const loadingFiles = {};
const lastProgress = { loaded: 0, total: 0 };
let progressFunc = null;
const 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;
this.setProgressFunc = function(callback) {
progressFunc = callback;
}
this.loadPromise = function(file) {
return new Promise(function(resolve, reject) {
loadXHR(resolve, reject, file, loadingFiles, DOWNLOAD_ATTEMPTS_MAX);
});
}
this.preloadedFiles = [];
this.preload = function(pathOrBuffer, destPath) {
let buffer = null;
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 if (pathOrBuffer instanceof ArrayBuffer) {
buffer = new Uint8Array(pathOrBuffer);
} else if (ArrayBuffer.isView(pathOrBuffer)) {
buffer = new Uint8Array(pathOrBuffer.buffer);
}
if (buffer) {
this.preloadedFiles.push({
path: destPath,
buffer: pathOrBuffer
});
return Promise.resolve();
} else {
return Promise.reject(new Error("Invalid object for preloading"));
}
};
};
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