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37 lines
1.2 KiB
37 lines
1.2 KiB
3 years ago
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'use strict';
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var global = require('../internals/global');
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var isArray = require('../internals/is-array');
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var lengthOfArrayLike = require('../internals/length-of-array-like');
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var bind = require('../internals/function-bind-context');
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var TypeError = global.TypeError;
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// `FlattenIntoArray` abstract operation
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// https://tc39.github.io/proposal-flatMap/#sec-FlattenIntoArray
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var flattenIntoArray = function (target, original, source, sourceLen, start, depth, mapper, thisArg) {
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var targetIndex = start;
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var sourceIndex = 0;
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var mapFn = mapper ? bind(mapper, thisArg) : false;
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var element, elementLen;
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while (sourceIndex < sourceLen) {
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if (sourceIndex in source) {
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element = mapFn ? mapFn(source[sourceIndex], sourceIndex, original) : source[sourceIndex];
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if (depth > 0 && isArray(element)) {
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elementLen = lengthOfArrayLike(element);
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targetIndex = flattenIntoArray(target, original, element, elementLen, targetIndex, depth - 1) - 1;
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} else {
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if (targetIndex >= 0x1FFFFFFFFFFFFF) throw TypeError('Exceed the acceptable array length');
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target[targetIndex] = element;
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}
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targetIndex++;
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}
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sourceIndex++;
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}
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return targetIndex;
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};
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module.exports = flattenIntoArray;
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