25 lines
903 B
JavaScript
25 lines
903 B
JavaScript
'use strict';
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var aFunction = require('./_a-function');
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var isObject = require('./_is-object');
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var invoke = require('./_invoke');
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var arraySlice = [].slice;
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var factories = {};
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var construct = function (F, len, args) {
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if (!(len in factories)) {
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for (var n = [], i = 0; i < len; i++) n[i] = 'a[' + i + ']';
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// eslint-disable-next-line no-new-func
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factories[len] = Function('F,a', 'return new F(' + n.join(',') + ')');
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} return factories[len](F, args);
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};
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module.exports = Function.bind || function bind(that /* , ...args */) {
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var fn = aFunction(this);
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var partArgs = arraySlice.call(arguments, 1);
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var bound = function (/* args... */) {
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var args = partArgs.concat(arraySlice.call(arguments));
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return this instanceof bound ? construct(fn, args.length, args) : invoke(fn, args, that);
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};
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if (isObject(fn.prototype)) bound.prototype = fn.prototype;
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return bound;
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};
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