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79 lines
2.8 KiB
JavaScript
79 lines
2.8 KiB
JavaScript
/**
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* lodash 3.1.2 (Custom Build) <https://lodash.com/>
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* Build: `lodash modern modularize exports="npm" -o ./`
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* Copyright 2012-2015 The Dojo Foundation <http://dojofoundation.org/>
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* Based on Underscore.js 1.8.3 <http://underscorejs.org/LICENSE>
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* Copyright 2009-2015 Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors
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* Available under MIT license <https://lodash.com/license>
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*/
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var baseCallback = require('lodash._basecallback'),
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baseEachRight = require('lodash._baseeachright'),
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baseReduce = require('lodash._basereduce'),
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isArray = require('lodash.isarray');
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/**
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* A specialized version of `_.reduceRight` for arrays without support for
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* callback shorthands and `this` binding.
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*
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* @private
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* @param {Array} array The array to iterate over.
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* @param {Function} iteratee The function invoked per iteration.
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* @param {*} [accumulator] The initial value.
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* @param {boolean} [initFromArray] Specify using the last element of `array`
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* as the initial value.
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* @returns {*} Returns the accumulated value.
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*/
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function arrayReduceRight(array, iteratee, accumulator, initFromArray) {
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var length = array.length;
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if (initFromArray && length) {
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accumulator = array[--length];
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}
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while (length--) {
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accumulator = iteratee(accumulator, array[length], length, array);
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}
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return accumulator;
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}
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/**
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* Creates a function for `_.reduce` or `_.reduceRight`.
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*
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* @private
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* @param {Function} arrayFunc The function to iterate over an array.
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* @param {Function} eachFunc The function to iterate over a collection.
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* @returns {Function} Returns the new each function.
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*/
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function createReduce(arrayFunc, eachFunc) {
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return function(collection, iteratee, accumulator, thisArg) {
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var initFromArray = arguments.length < 3;
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return (typeof iteratee == 'function' && thisArg === undefined && isArray(collection))
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? arrayFunc(collection, iteratee, accumulator, initFromArray)
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: baseReduce(collection, baseCallback(iteratee, thisArg, 4), accumulator, initFromArray, eachFunc);
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};
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}
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/**
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* This method is like `_.reduce` except that it iterates over elements of
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* `collection` from right to left.
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*
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* @static
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* @memberOf _
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* @alias foldr
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* @category Collection
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* @param {Array|Object|string} collection The collection to iterate over.
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* @param {Function} [iteratee=_.identity] The function invoked per iteration.
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* @param {*} [accumulator] The initial value.
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* @param {*} [thisArg] The `this` binding of `iteratee`.
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* @returns {*} Returns the accumulated value.
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* @example
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*
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* var array = [[0, 1], [2, 3], [4, 5]];
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*
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* _.reduceRight(array, function(flattened, other) {
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* return flattened.concat(other);
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* }, []);
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* // => [4, 5, 2, 3, 0, 1]
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*/
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var reduceRight = createReduce(arrayReduceRight, baseEachRight);
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module.exports = reduceRight;
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