What this snippet does
Generics don't create overloads for mixed types; they infer a union, meaning the return type is the union, not the specific input type.
Expected output
string | number
Why practise typing this
Typing advanced generics 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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