uniq.js
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var baseCallback = require('../internal/baseCallback'),
baseUniq = require('../internal/baseUniq'),
isIterateeCall = require('../internal/isIterateeCall'),
sortedUniq = require('../internal/sortedUniq');
/**
* Creates a duplicate-free version of an array, using
* [`SameValueZero`](http://ecma-international.org/ecma-262/6.0/#sec-samevaluezero)
* for equality comparisons, in which only the first occurence of each element
* is kept. Providing `true` for `isSorted` performs a faster search algorithm
* for sorted arrays. If an iteratee function is provided it's invoked for
* each element in the array to generate the criterion by which uniqueness
* is computed. The `iteratee` is bound to `thisArg` and invoked with three
* arguments: (value, index, array).
*
* If a property name is provided for `iteratee` the created `_.property`
* style callback returns the property value of the given element.
*
* If a value is also provided for `thisArg` the created `_.matchesProperty`
* style callback returns `true` for elements that have a matching property
* value, else `false`.
*
* If an object is provided for `iteratee` the created `_.matches` style
* callback returns `true` for elements that have the properties of the given
* object, else `false`.
*
* @static
* @memberOf _
* @alias unique
* @category Array
* @param {Array} array The array to inspect.
* @param {boolean} [isSorted] Specify the array is sorted.
* @param {Function|Object|string} [iteratee] The function invoked per iteration.
* @param {*} [thisArg] The `this` binding of `iteratee`.
* @returns {Array} Returns the new duplicate-value-free array.
* @example
*
* _.uniq([2, 1, 2]);
* // => [2, 1]
*
* // using `isSorted`
* _.uniq([1, 1, 2], true);
* // => [1, 2]
*
* // using an iteratee function
* _.uniq([1, 2.5, 1.5, 2], function(n) {
* return this.floor(n);
* }, Math);
* // => [1, 2.5]
*
* // using the `_.property` callback shorthand
* _.uniq([{ 'x': 1 }, { 'x': 2 }, { 'x': 1 }], 'x');
* // => [{ 'x': 1 }, { 'x': 2 }]
*/
function uniq(array, isSorted, iteratee, thisArg) {
var length = array ? array.length : 0;
if (!length) {
return [];
}
if (isSorted != null && typeof isSorted != 'boolean') {
thisArg = iteratee;
iteratee = isIterateeCall(array, isSorted, thisArg) ? undefined : isSorted;
isSorted = false;
}
iteratee = iteratee == null ? iteratee : baseCallback(iteratee, thisArg, 3);
return (isSorted)
? sortedUniq(array, iteratee)
: baseUniq(array, iteratee);
}
module.exports = uniq;