36 lines
1.1 KiB
JavaScript
36 lines
1.1 KiB
JavaScript
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var baseCallback = require('./baseCallback'),
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baseEach = require('./baseEach'),
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isArray = require('../lang/isArray');
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/**
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* Creates a `_.countBy`, `_.groupBy`, `_.indexBy`, or `_.partition` function.
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*
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* @private
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* @param {Function} setter The function to set keys and values of the accumulator object.
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* @param {Function} [initializer] The function to initialize the accumulator object.
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* @returns {Function} Returns the new aggregator function.
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*/
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function createAggregator(setter, initializer) {
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return function(collection, iteratee, thisArg) {
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var result = initializer ? initializer() : {};
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iteratee = baseCallback(iteratee, thisArg, 3);
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if (isArray(collection)) {
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var index = -1,
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length = collection.length;
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while (++index < length) {
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var value = collection[index];
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setter(result, value, iteratee(value, index, collection), collection);
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}
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} else {
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baseEach(collection, function(value, key, collection) {
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setter(result, value, iteratee(value, key, collection), collection);
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});
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}
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return result;
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};
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}
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module.exports = createAggregator;
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