Edit File: sumBy.js
var baseIteratee = require('./_baseIteratee'), baseSum = require('./_baseSum'); /** * This method is like `_.sum` except that it accepts `iteratee` which is * invoked for each element in `array` to generate the value to be summed. * The iteratee is invoked with one argument: (value). * * @static * @memberOf _ * @since 4.0.0 * @category Math * @param {Array} array The array to iterate over. * @param {Function} [iteratee=_.identity] The iteratee invoked per element. * @returns {number} Returns the sum. * @example * * var objects = [{ 'n': 4 }, { 'n': 2 }, { 'n': 8 }, { 'n': 6 }]; * * _.sumBy(objects, function(o) { return o.n; }); * // => 20 * * // The `_.property` iteratee shorthand. * _.sumBy(objects, 'n'); * // => 20 */ function sumBy(array, iteratee) { return (array && array.length) ? baseSum(array, baseIteratee(iteratee, 2)) : 0; } module.exports = sumBy;
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