Tiny utility to create unions and de-duplicated lists.

Example:

var uniqs = require('uniqs');

var foo = { foo: 23 };
var list = [3, 2, 2, 1, foo, foo];

uniqs(list);
// => [3, 2, 1, { foo: 23 }]

You can pass multiple lists to create a union:

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

Passing individual items works too:

uniqs(3, 2, 2, [1, 1, 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:

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

License

MIT