What this snippet does
Wrapping types in tuples prevents distribution, resulting in a single array of the union type rather than a union of arrays.
Expected output
[ 'a', 1 ]
Why practise typing this
Typing conditional types 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
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- Inferring from a non-matching typeConditional Types · intermediate