question: How can I validate a union of strings?

[stefan-bc-ts]

I was trying to...
use export type ValidateValues = ‘val1’ | ‘val2’ | ‘val3’;
with @type to make sure the values are correct

The problem:

@Type((_) => ValidateValues)
'ValidateValues' only refers to a type, but is being used as a value here

PS: I was trying to avoid using a enum

[braaar]

I'm moving this to the discussion tab, as we are trying to keep the issue count low. Please see this issue for an explanation.

[jessekernaghan]

For anyone coming across this, I have been solving this by declaring an array as const and then using it with @IsIn(), i.e.:

const validateValues = ['val1', 'val2', 'val3'] as const; // note the 'as const'
type ValidateValues = (typeof validateValues)[number]; // produces 'val1' | 'val2' | 'val3'

class MyClass {
  @IsIn(validateValues)
  type: ValidateValues;
}