Implemented according to upcoming ECMAScript6 standard, plus few non standard extensions
var Set = require('set-collection');
var set = new Set([23, 'foo', { lorem: true }]);
set.has('foo'); // true
set.add('bar');
set.delete(23);
console.log(set.values); // ['foo', 'bar', { lorem: true }];
In your project path:
$ npm install set-collection
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$ npm test