[majewsky]

Nearly every time I write something in JavaScript, the first line is const $ = (selector) => document.querySelector(selector). I do not have jQuery nostalgia as much as many others here, but that particular shorthand is very useful.

For extra flavor, const $$ = (selector) => document.querySelectorAll(selector) on top.

[SahAssar]

    const $$ = (selector) => Array.from(document.querySelectorAll(selector))

is even nicer since then you can do things like

    $$('.myclass').map(e => stuff)