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51 lines
1.3 KiB
JavaScript
51 lines
1.3 KiB
JavaScript
9 years ago
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var arraySum = require('../internal/arraySum'),
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baseCallback = require('../internal/baseCallback'),
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baseSum = require('../internal/baseSum'),
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isArray = require('../lang/isArray'),
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isIterateeCall = require('../internal/isIterateeCall'),
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toIterable = require('../internal/toIterable');
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/**
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* Gets the sum of the values in `collection`.
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*
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* @static
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* @memberOf _
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* @category Math
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* @param {Array|Object|string} collection The collection to iterate over.
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* @param {Function|Object|string} [iteratee] The function invoked per iteration.
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* @param {*} [thisArg] The `this` binding of `iteratee`.
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* @returns {number} Returns the sum.
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* @example
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*
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* _.sum([4, 6]);
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* // => 10
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*
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* _.sum({ 'a': 4, 'b': 6 });
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* // => 10
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*
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* var objects = [
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* { 'n': 4 },
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* { 'n': 6 }
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* ];
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*
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* _.sum(objects, function(object) {
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* return object.n;
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* });
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* // => 10
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*
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* // using the `_.property` callback shorthand
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* _.sum(objects, 'n');
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* // => 10
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*/
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function sum(collection, iteratee, thisArg) {
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if (thisArg && isIterateeCall(collection, iteratee, thisArg)) {
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iteratee = undefined;
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}
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iteratee = baseCallback(iteratee, thisArg, 3);
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return iteratee.length == 1
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? arraySum(isArray(collection) ? collection : toIterable(collection), iteratee)
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: baseSum(collection, iteratee);
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}
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module.exports = sum;
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