This is a reference entry from TypeScript diagnosticMessages.json. A full explanation with fixes has not been written yet.
A labeled tuple element is declared as optional with a question mark after the name and before the colon, rather than after the type.
{0}, {1} and so on are filled in by the compiler.
- Category
- Error
- Severity
- error
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Source: TypeScript diagnosticMessages.json. Data fetched 2026-09-25T01:43:12.676Z.