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allow constants for string literals types #6151
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We can't do this since it would be a breaking change --
vowhas not previously introduced an entry in the type namespace, so doing so now would mean random types would start getting shadowed.typeof vowshould do what you want here (if we madeconsts be of their string literal type Daniel Rosenwasser (@DanielRosenwasser) please confirm?).typeof vowshould do what you want herein the expression context
typeof vowgets me"string"
in the type expression context it gets me"will never change", but it's a string literal type which I cannot assign to a variable... if we made consts be of their string literal type
if we assuming it's hasn't yet been done, then it answers it
Like Ryan Cavanaugh (@RyanCavanaugh) said, in order to do
typeof vow, you'd need #5796. That said, I don't know if that PR will go in. The behavior isn't entirely ideal because it's not clear when you want the literal type and notstring.Here is the proposal: #6167 (comment)
What about allowing interpolated strings as string literal types. So:
const vow = "will never change"; let promise: `${vow}`;The issue in the OP should be fixed by #10676
Allowing string interpolation, or any form of string manipulation in type positions is not something we are looking to allow.
for this specific example, use
typeofoperator, e.g.let promise: typeof vow;and this should be"will never change".Reacted by Aluan Haddad, Erik Cupal, Daniel García, Steve Dignam, Adam Szmyd and Yurii KozhenovReacted by Erik Cupal, Daniel García and Adam SzmydReacted by Erik Cupal and Daniel García- modified the milestone:
on Dec 1, 2016 Aleksey-Bykov do you agree this proposal is covered by #10676 and
typeof?yes, it's solved, please clise
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on Jun 19, 2018
