includes.js
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define(['../internal/baseIndexOf', '../internal/getLength', '../lang/isArray', '../internal/isIterateeCall', '../internal/isLength', '../lang/isString', '../object/values'], function(baseIndexOf, getLength, isArray, isIterateeCall, isLength, isString, values) {
/* Native method references for those with the same name as other `lodash` methods. */
var nativeMax = Math.max;
/**
* Checks if `target` is in `collection` using
* [`SameValueZero`](http://ecma-international.org/ecma-262/6.0/#sec-samevaluezero)
* for equality comparisons. If `fromIndex` is negative, it's used as the offset
* from the end of `collection`.
*
* @static
* @memberOf _
* @alias contains, include
* @category Collection
* @param {Array|Object|string} collection The collection to search.
* @param {*} target The value to search for.
* @param {number} [fromIndex=0] The index to search from.
* @param- {Object} [guard] Enables use as a callback for functions like `_.reduce`.
* @returns {boolean} Returns `true` if a matching element is found, else `false`.
* @example
*
* _.includes([1, 2, 3], 1);
* // => true
*
* _.includes([1, 2, 3], 1, 2);
* // => false
*
* _.includes({ 'user': 'fred', 'age': 40 }, 'fred');
* // => true
*
* _.includes('pebbles', 'eb');
* // => true
*/
function includes(collection, target, fromIndex, guard) {
var length = collection ? getLength(collection) : 0;
if (!isLength(length)) {
collection = values(collection);
length = collection.length;
}
if (typeof fromIndex != 'number' || (guard && isIterateeCall(target, fromIndex, guard))) {
fromIndex = 0;
} else {
fromIndex = fromIndex < 0 ? nativeMax(length + fromIndex, 0) : (fromIndex || 0);
}
return (typeof collection == 'string' || !isArray(collection) && isString(collection))
? (fromIndex <= length && collection.indexOf(target, fromIndex) > -1)
: (!!length && baseIndexOf(collection, target, fromIndex) > -1);
}
return includes;
});