39 lines
1.2 KiB
JavaScript
39 lines
1.2 KiB
JavaScript
|
'use strict';
|
||
|
|
var $ = require('../internals/export');
|
||
|
|
var toLength = require('../internals/to-length');
|
||
|
|
var toObject = require('../internals/to-object');
|
||
|
|
var getBuiltIn = require('../internals/get-built-in');
|
||
|
|
var arraySpeciesCreate = require('../internals/array-species-create');
|
||
|
|
var addToUnscopables = require('../internals/add-to-unscopables');
|
||
|
|
|
||
|
|
var push = [].push;
|
||
|
|
|
||
|
|
// `Array.prototype.uniqueBy` method
|
||
|
|
// https://github.com/tc39/proposal-array-unique
|
||
|
|
$({ target: 'Array', proto: true }, {
|
||
|
|
uniqueBy: function uniqueBy(resolver) {
|
||
|
|
var that = toObject(this);
|
||
|
|
var length = toLength(that.length);
|
||
|
|
var result = arraySpeciesCreate(that, 0);
|
||
|
|
var Map = getBuiltIn('Map');
|
||
|
|
var map = new Map();
|
||
|
|
var resolverFunction, index, item, key;
|
||
|
|
if (typeof resolver == 'function') resolverFunction = resolver;
|
||
|
|
else if (resolver == null) resolverFunction = function (value) {
|
||
|
|
return value;
|
||
|
|
};
|
||
|
|
else throw new TypeError('Incorrect resolver!');
|
||
|
|
for (index = 0; index < length; index++) {
|
||
|
|
item = that[index];
|
||
|
|
key = resolverFunction(item);
|
||
|
|
if (!map.has(key)) map.set(key, item);
|
||
|
|
}
|
||
|
|
map.forEach(function (value) {
|
||
|
|
push.call(result, value);
|
||
|
|
});
|
||
|
|
return result;
|
||
|
|
}
|
||
|
|
});
|
||
|
|
|
||
|
|
addToUnscopables('uniqueBy');
|