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