Már Örlygsson :nerd:Dec 20, 2022

Ran into a bug where TypeScript infers that an empty array (literal `[]`) to be of type `never[]`, which it interprets to never happen and thus to be of no sigificance.

Runtime errors then ensue.

https://www.typescriptlang.org/play?#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Show threadMár Örlygsson :nerd:
Bug reported: https://github.com/microsoft/TypeScript/issues/51979
Empty array (`[]`) inferred to be `never[]` instead of `[]` or `undefined[]` · Issue #51979 · microsoft/TypeScript

Bug Report I ran into this behavior where TypeScript infers that an empty array (literal []) to be of type never[], which it interprets to never happen and thus to be of no sigificance. Runtime err...

GitHub
Dec 20, 2022 at 6:04pmWeb
Show threadMár Örlygsson :nerd:Dec 29, 2022

Amazingly this is TypeScript "working as intended": https://github.com/microsoft/TypeScript/issues/51979

😜😬🫣

Empty array (`[]`) inferred to be `never[]` instead of `[]` or `undefined[]` · Issue #51979 · microsoft/TypeScript

Bug Report I ran into this behavior where TypeScript infers that an empty array (literal []) to be of type never[], which it interprets to never happen and thus to be of no sigificance. Runtime err...

GitHub