let n = 1 as const
const o = { a1: "abcd" }
const x = o[`a${n}`]
// ^? : string
const { [`a${n}`]: y } = o
// ^? Errors: Type '{ a1: string; }' has no matching index signature for type 'string'.(2537)
π Actual behavior
`a${n}` in object destruction not inferred as const ("a1")
π Expected behavior
`a${n}` in object destruction should be inferred as "a1", just like the one in element access.
Additional information about the issue
A possible workaround is to add as const after `a${n}`. I think the main problem is the inconsistency between element access and object destruction, which is confusing.
π Search Terms
destruct object
π Version & Regression Information
Before
v4.4.4
, index expression in element access was also not inferred as const. So this issue starts fromv4.4.4
. Reproducible in Nightly build.β― Playground Link
https://www.typescriptlang.org/play/#code/DYUwLgBAdhC8EEYIEMDOEDGB7KqwChtdIs4IBvFBALggCIE6V0i8IBffQnNgDzKwBtAAbIAJOSjthAXXwB6eRGUQAegH5uxChBHjJ0mbQCeHAfiA
π» Code
π Actual behavior
`a${n}`
in object destruction not inferred as const ("a1"
)π Expected behavior
`a${n}`
in object destruction should be inferred as"a1"
, just like the one in element access.Additional information about the issue
A possible workaround is to add
as const
after`a${n}`
. I think the main problem is the inconsistency between element access and object destruction, which is confusing.