| 1 | import baseIteratee from './_baseIteratee';
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| 2 | import baseSum from './_baseSum';
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| 3 |
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| 4 | /**
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| 5 | * This method is like `_.sum` except that it accepts `iteratee` which is
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| 6 | * invoked for each element in `array` to generate the value to be summed.
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| 7 | * The iteratee is invoked with one argument: (value).
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| 8 | *
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| 9 | * @static
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| 10 | * @memberOf _
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| 11 | * @since 4.0.0
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| 12 | * @category Math
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| 13 | * @param {Array} array The array to iterate over.
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| 14 | * @param {Array|Function|Object|string} [iteratee=_.identity]
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| 15 | * The iteratee invoked per element.
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| 16 | * @returns {number} Returns the sum.
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| 17 | * @example
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| 18 | *
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| 19 | * var objects = [{ 'n': 4 }, { 'n': 2 }, { 'n': 8 }, { 'n': 6 }];
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| 20 | *
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| 21 | * _.sumBy(objects, function(o) { return o.n; });
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| 22 | * // => 20
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| 23 | *
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| 24 | * // The `_.property` iteratee shorthand.
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| 25 | * _.sumBy(objects, 'n');
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| 26 | * // => 20
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| 27 | */
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| 28 | function sumBy(array, iteratee) {
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| 29 | return (array && array.length)
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| 30 | ? baseSum(array, baseIteratee(iteratee))
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| 31 | : 0;
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| 32 | }
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| 33 |
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| 34 | export default sumBy;
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