What this snippet does
If an array contains mixed types on initialization, TypeScript infers a union array type, rejecting incompatible pushes.
Expected output
Compile Error: Argument of type 'boolean' is not assignable to parameter of type 'string | number'.
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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