MC.07.01 Mid-levelCore — asked often

Modal and toast system as a reusable API

Comes up in: Machine coding, Low-level design

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

imperative API (toast.success()), provider + portal
stacking multiple modals
scroll lock
focus restoration
queue limits and priorities
animations with reduced motion

Words you will know

imperative APIportal

What you will practise

build useToast() and useModal() APIs (timed 75 min)

Interview questions this answers

Design an API for a toast system used across a large app.
How do you handle multiple stacked modals?