1 | var baseIndexOf = require('./_baseIndexOf'),
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2 | toInteger = require('./toInteger');
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3 |
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4 | /* Built-in method references for those with the same name as other `lodash` methods. */
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5 | var nativeMax = Math.max;
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6 |
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7 | /**
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8 | * Gets the index at which the first occurrence of `value` is found in `array`
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9 | * using [`SameValueZero`](http://ecma-international.org/ecma-262/7.0/#sec-samevaluezero)
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10 | * for equality comparisons. If `fromIndex` is negative, it's used as the
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11 | * offset from the end of `array`.
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12 | *
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13 | * @static
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14 | * @memberOf _
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15 | * @since 0.1.0
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16 | * @category Array
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17 | * @param {Array} array The array to inspect.
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18 | * @param {*} value The value to search for.
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19 | * @param {number} [fromIndex=0] The index to search from.
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20 | * @returns {number} Returns the index of the matched value, else `-1`.
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21 | * @example
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22 | *
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23 | * _.indexOf([1, 2, 1, 2], 2);
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24 | * // => 1
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25 | *
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26 | * // Search from the `fromIndex`.
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27 | * _.indexOf([1, 2, 1, 2], 2, 2);
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28 | * // => 3
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29 | */
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30 | function indexOf(array, value, fromIndex) {
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31 | var length = array == null ? 0 : array.length;
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32 | if (!length) {
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33 | return -1;
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34 | }
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35 | var index = fromIndex == null ? 0 : toInteger(fromIndex);
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36 | if (index < 0) {
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37 | index = nativeMax(length + index, 0);
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38 | }
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39 | return baseIndexOf(array, value, index);
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40 | }
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41 |
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42 | module.exports = indexOf;
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