Typescript: String literal type with custom parameter`

Question

I am attempting to define a string literal type that has a variable parameter in it.

eg:

type myStringType = 'a' | 'b' | 'c' | `d[${parameter}]`

I'd like the string d[parameter] to accept anything which resembles d[foo] or d[bar]

Edited: added back ticks to template literal, though i'm not attached to this being a template literal and if there is another solution...

Answer 1

Starting from Typescript 4.1, you can use template literal types .

type parameter = "foo" | "bar"

type myStringType = 'a' | 'b' | 'c' | `d[${parameter}]`

// type myStringType = "a" | "b" | "c" | "d[foo]" | "d[bar]"