What this snippet does
Spreading a generic tuple U after a fixed type T creates a new tuple with T at the front and U's elements following.
Expected output
[ 'id', 1, 2 ]
Why practise typing this
Typing advanced tuples 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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- Labels do not create object propertiesAdvanced Tuples · advanced
- Declaring variables with primitive typesBasic Types · beginner