What this snippet does
The return type annotation is strictly enforced, preventing functions from leaking unexpected types.
Expected output
Compile Error: Type 'string' is not assignable to type 'number'.
Why practise typing this
Typing functions 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.
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