What this snippet does
Optional parameters (denoted with ?) must come after required parameters and can be undefined.
Expected output
a@b.com: No Subject
Why practise typing this
Typing functions 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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