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var baseIndexOf = require('../internal/baseIndexOf'),
binaryIndex = require('../internal/binaryIndex');
/* Native method references for those with the same name as other `lodash` methods. */
var nativeMax = Math.max;
/**
* Gets the index at which the first occurrence of `value` is found in `array`
* using `SameValueZero` for equality comparisons. If `fromIndex` is negative,
* it is used as the offset from the end of `array`. If `array` is sorted
* providing `true` for `fromIndex` performs a faster binary search.
*
* **Note:** `SameValueZero` comparisons are like strict equality comparisons,
* e.g. `===`, except that `NaN` matches `NaN`. See the
* [ES spec](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-samevaluezero)
* for more details.
*
* @static
* @memberOf _
* @category Array
* @param {Array} array The array to search.
* @param {*} value The value to search for.
* @param {boolean|number} [fromIndex=0] The index to search from or `true`
* to perform a binary search on a sorted array.
* @returns {number} Returns the index of the matched value, else `-1`.
* @example
*
* _.indexOf([1, 2, 3, 1, 2, 3], 2);
* // => 1
*
* // using `fromIndex`
* _.indexOf([1, 2, 3, 1, 2, 3], 2, 3);
* // => 4
*
* // performing a binary search
* _.indexOf([4, 4, 5, 5, 6, 6], 5, true);
* // => 2
*/
function indexOf(array, value, fromIndex) {
var length = array ? array.length : 0;
if (!length) {
return -1;
}
if (typeof fromIndex == 'number') {
fromIndex = fromIndex < 0 ? nativeMax(length + fromIndex, 0) : (fromIndex || 0);
} else if (fromIndex) {
var index = binaryIndex(array, value),
other = array[index];
return (value === value ? value === other : other !== other) ? index : -1;
}
return baseIndexOf(array, value, fromIndex);
}
module.exports = indexOf;
Version data entries
14 entries across 7 versions & 1 rubygems