What this snippet does
No value can be assigned to 'never' because it represents an impossible state or function that never returns.
Expected output
Compile Error: Type 'number' is not assignable to type 'never'.
Why practise typing this
Typing type system limits 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
- Contrasting any, unknown, and neverType System Limits · advanced
- Using never to filter union typesType System Limits · advanced
- Deeply nested type instantiationType System Limits · advanced
- Exceeding tuple recursion limitsType System Limits · advanced
- Infinite conditional type distributionType System Limits · advanced
- Defining a circular type referenceType System Limits · advanced