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Reimplement the tools — debounce, Promise, router, virtual DOM.
Difficulty mix 30 questions · 5 categories
- Easy 5 17%
- Medium 15 50%
- Hard 10 33%
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Where to go next
📚 Learn & practice
Prompts get you drilling; these get you learning. Hand-picked, canonical sources — read the concept, then go deep.
Read
- javascript.info javascript.info
The internals you're reimplementing, explained first.
- MDN — Promise developer.mozilla.org
The spec behavior to match when you rebuild it.
- Tania Rascia — Understanding 'this' & prototypes taniarascia.com
The mechanics behind bind/call/apply.
Practice
- BigFrontEnd.dev bigfrontend.dev
Implement debounce, Promise.all, etc. against tests.
- GreatFrontEnd — JS utilities greatfrontend.com
Reimplement lodash/DOM utilities with solutions.
- CodeSandbox codesandbox.io
A quick playground to build and test your versions.