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32 lines
1.1 KiB
32 lines
1.1 KiB
'use strict'; |
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var isArray = require('../internals/is-array'); |
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var toLength = require('../internals/to-length'); |
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var bind = require('../internals/function-bind-context'); |
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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, 3) : false; |
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var element; |
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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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targetIndex = flattenIntoArray(target, original, element, toLength(element.length), 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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