Microsoft/TypeScript

typeof Foo['bar'] has strange precedence

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#19,707 创建于 2017年11月3日

 (6 条评论) (0 个反应) (0 位负责人)TypeScript (13,395 个派生)batch import
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描述

Type queries combined with indexed access types currently produce a parse tree that is surprising in its behavior.

One would think that typeof Foo['bar'] would be parsed as typeof (Foo['bar']), which would really be something like typeof Foo.bar.

That's not the case. It's actually parsed as (typeof Foo)['bar'].

Conveniently, it seems that semantically (when type-checking) these are identical, but it seems strange for syntactic consumers. Do we believe this is currently working as intended?

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