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- 'use strict';
-
- // there's 3 implementations written in increasing order of efficiency
-
- // 1 - no Set type is defined
- function uniqNoSet(arr) {
- var ret = [];
-
- for (var i = 0; i < arr.length; i++) {
- if (ret.indexOf(arr[i]) === -1) {
- ret.push(arr[i]);
- }
- }
-
- return ret;
- }
-
- // 2 - a simple Set type is defined
- function uniqSet(arr) {
- var seen = new Set();
- return arr.filter(function (el) {
- if (!seen.has(el)) {
- seen.add(el);
- return true;
- }
-
- return false;
- });
- }
-
- // 3 - a standard Set type is defined and it has a forEach method
- function uniqSetWithForEach(arr) {
- var ret = [];
-
- (new Set(arr)).forEach(function (el) {
- ret.push(el);
- });
-
- return ret;
- }
-
- // V8 currently has a broken implementation
- // https://github.com/joyent/node/issues/8449
- function doesForEachActuallyWork() {
- var ret = false;
-
- (new Set([true])).forEach(function (el) {
- ret = el;
- });
-
- return ret === true;
- }
-
- if ('Set' in global) {
- if (typeof Set.prototype.forEach === 'function' && doesForEachActuallyWork()) {
- module.exports = uniqSetWithForEach;
- } else {
- module.exports = uniqSet;
- }
- } else {
- module.exports = uniqNoSet;
- }
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