underscore and harmony clear solution for [old] Non-unique Elements by oduvan - javascript coding challenges

Enable Javascript in your browser and then refresh this page, for a much enhanced experience.

underscore and harmony solution in Clear category for [old] Non-unique Elements by oduvan

"use strict";

var _ = require("underscore");

function checkio(data) {
    return _.filter(data, a => {
        return data.indexOf(a) !== data.lastIndexOf(a)    
    });
}

June 21, 2016

Comments:

nickie on Sept. 8, 2016, 9:56 p.m.
Nice and clean. Three comments. <ol> <li>As `indexOf` and `lastIndexOf` take O(N) time, this solution is O(N^2).</li> <li>Why use the underscore? You can do the same with standard array `data.filter`.</li> <li>Why use a compound body for the arrow function, if it only contains a `return`?.</li> </ol> By following the last two suggestions and tweaking it a little bit, you can come up with a 1-liner: <pre class='brush: javascript'>let checkio = data => data.filter(a => data.indexOf(a) !== data.lastIndexOf(a)); </pre>

oduvan on Sept. 9, 2016, 1:52 p.m.
thanks. I agree. Still a lot of things to learn

Amazzzonka on Sept. 9, 2016, 9:03 a.m.
Underscore isn't needed, you can use standard array.filter() method.

oduvan on Sept. 9, 2016, 1:51 p.m.
Agree here

No Station

WebStorm The smartest JavaScript IDE. WebStorm is a powerful JavaScript IDE that makes you productive. Try free!