33 lines
784 B
JavaScript
33 lines
784 B
JavaScript
Array.prototype.filter = function(fun/*, thisArg*/) {
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'use strict';
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if (this === void 0 || this === null) {
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throw new TypeError();
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}
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var t = Object(this);
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var len = t.length >>> 0;
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if (typeof fun !== 'function') {
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throw new TypeError();
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}
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var res = [];
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var thisArg = arguments.length >= 2 ? arguments[1] : void 0;
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for (var i = 0; i < len; i++) {
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if (i in t) {
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var val = t[i];
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// NOTE: Technically this should Object.defineProperty at
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// the next index, as push can be affected by
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// properties on Object.prototype and Array.prototype.
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// But that method's new, and collisions should be
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// rare, so use the more-compatible alternative.
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if (fun.call(thisArg, val, i, t)) {
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res.push(val);
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}
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}
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}
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return res;
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};
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