Typescript const Enum issue

Question

I have declared the following enum in my Typescript file:

export const enum INPUT_PATTERNS{
    ALL          = ".*",
    ONLY_NUMBERS = "[0-9]*"

}

During compilation, I keep on getting the following error message:

In 'const' enum declarations member initializer must be constant expression.

I have initialized the enums with constant values and so I dont understand whats wrong here?

Secondly, if I remove the const identifier from enum as follows:

export enum INPUT_PATTERNS{
    ALL          = ".*",
    ONLY_NUMBERS = "[0-9]*"

}

then I get the following error:

Type '"."' is not assignable to type 'INPUT_PATTERNS'.
Type '"[0-9]"' is not assignable to type 'INPUT_PATTERNS'.

toskv · Accepted Answer · 2017-02-03 13:11:22Z

1

You could do:

export enum INPUT_PATTERNS{
    ALL          = <any>".*",
    ONLY_NUMBERS = <any>"[0-9]*" 

}

answered Feb 3, 2017 at 13:11

toskv

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Comments

Markus · Accepted Answer · 2017-02-03 13:21:46Z

1

Enums allow us to define a set of named numeric constants. http://www.typescriptlang.org/docs/handbook/enums.html

You can use a combination of namespace and const variables:

export namespace INPUT_PATTERNS {
    export const ALL = ".*";
    export const ONLY_NUMBERS = "[0-9]*";
}

answered Feb 3, 2017 at 13:21

Markus

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