Tiny utility to create unions and de-duplicated lists.

Example:

1var uniqs = require('uniqs');
2
3var foo = { foo: 23 };
4var list = [3, 2, 2, 1, foo, foo];
5
6uniqs(list);
7// => [3, 2, 1, { foo: 23 }]

You can pass multiple lists to create a union:

1uniqs([2, 1, 1], [2, 3, 3, 4], [4, 3, 2]);
2// => [2, 1, 3, 4]

Passing individual items works too:

1uniqs(3, 2, 2, [1, 1, 2]);
2// => [3, 2, 1]

Summary

• Uniqueness is defined based on strict object equality.
• The lists do not need to be sorted.
• The resulting array contains the items in the order of their first appearance.

About

This package has been written to accompany utilities like flatten as alternative to full-blown libraries like underscore or lodash.

The implementation is optimized for simplicity rather than performance and looks like this:

1module.exports = function uniqs() {
2  var list = Array.prototype.concat.apply([], arguments);
3  return list.filter(function(item, i) {
4    return i == list.indexOf(item);
5  });
6};

License

MIT