What this snippet does
Symbols create completely unique property keys that won't collide with any string-based properties.
Expected output
42
Why practise typing this
Typing symbols & iterators code builds muscle memory for the symbols and indentation TypeScript uses most, which prose-based typing tests never cover. DevType measures your words per minute and accuracy on this snippet and tracks the individual characters you mistype, so later lessons can target them.
More TypeScript practice
- Using Symbol.iterator to make an object iterableSymbols & Iterators · advanced
- Accessing symbol properties with string keysSymbols & Iterators · advanced
- Implementing a basic iterator interfaceSymbols & Iterators · advanced
- Custom collection iterator with done stateSymbols & Iterators · advanced
- Forgetting to return done: trueSymbols & Iterators · advanced
- Creating a basic generator functionSymbols & Iterators · advanced