JS.16.09 Mid-levelCore — asked often

DOM utilities

Comes up in: Coding, UI coding

This concept is being written. It gets the full five steps — explanation, predict, interview angle, practice with tests, and review cards. Here is exactly what it will cover, so you can study it elsewhere in the meantime.

What it covers

getElementsByClassName / querySelectorAll subset via tree walk
event delegation helper with closest
serialize DOM to JSON and back
find a node in a cloned tree (path of indices)
virtual-DOM render(vnode) plus diff/patch

Words you will know

tree walkvirtual DOM

What you will practise

implement 4 DOM utilities

Interview questions this answers

Implement getElementsByClassName without using built-in selectors.