What are basic essential features of Javascript while working on web development projects?

Question

Basics like dom manipulation, event listeners, selectors etc

Answer 1

I think you've listed them.

Answer 2

Web projects can be greatly varied in their differences. Knowing some APIs that allow to do the work quickly might help too.
The ones you've listed are common, I feel, in every project.

Answer 3

By your side If you can add something then that would be quite helpful..