Typescript const枚举问题

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'.

Answer 1

You could do:

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

}

Answer 2

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]*";
}