TypeScript

Type widening of const variables to their literal type in TypeScript

TypeScriptVariables and DeclarationsType Wideningbeginner

What this snippet does

Constants do not widen to their base type, whereas variables assigned from them do, causing unexpected type errors.

Expected output

Compile Error: Type '"right"' is not assignable to type '"left"'.

Why practise typing this

Typing variables and declarations 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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