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