Narrow from 'any' in most situations #10334
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instanceof and user-defined typeguards narrow from 'any' unless the narrowed-to type is exactly 'Object' or 'Function'. This is a breaking change.
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Hi @yortus, I'm your friendly neighborhood Microsoft Pull Request Bot (You can call me MSBOT). Thanks for your contribution! TTYL, MSBOT; |
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Existential crisis averted. Clearly it's because this PR title starts with an uppercase 'N'. |
5 tasks
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👍 and an extra 🍺 for updating the comments in the testcases |
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| else if (err instanceof Error) { | ||
| err.message; | ||
| err.massage; // ERROR: Property 'massage' does not exist on type 'Error' |
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If only errors came with massages.
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Thanks for the change along with those test cases! |
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Thanks for the guidance. |
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Supersedes #10319 which has weird CI build problems.
This PR implements narrowing from
anyas described in #9999 (comment).NB: this is a breaking change.
Fixes #9999, #10000, #8677
Checklist:
instanceofor a user-defined type predicate will narrow unless the narrowed-to type is exactlyFunctionor exactlyObject(in which case the expression remains of typeany)jake runtestslocally