39 lines
1.2 KiB
JavaScript
39 lines
1.2 KiB
JavaScript
var arrayPush = require('./_arrayPush'),
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isFlattenable = require('./_isFlattenable');
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/**
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* The base implementation of `_.flatten` with support for restricting flattening.
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*
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* @private
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* @param {Array} array The array to flatten.
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* @param {number} depth The maximum recursion depth.
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* @param {boolean} [predicate=isFlattenable] The function invoked per iteration.
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* @param {boolean} [isStrict] Restrict to values that pass `predicate` checks.
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* @param {Array} [result=[]] The initial result value.
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* @returns {Array} Returns the new flattened array.
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*/
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function baseFlatten(array, depth, predicate, isStrict, result) {
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var index = -1,
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length = array.length;
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predicate || (predicate = isFlattenable);
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result || (result = []);
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while (++index < length) {
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var value = array[index];
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if (depth > 0 && predicate(value)) {
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if (depth > 1) {
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// Recursively flatten arrays (susceptible to call stack limits).
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baseFlatten(value, depth - 1, predicate, isStrict, result);
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} else {
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arrayPush(result, value);
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}
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} else if (!isStrict) {
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result[result.length] = value;
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}
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}
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return result;
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}
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module.exports = baseFlatten;
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