Get String of a TypeScript String Enum

Question

The string of an enum can be obtained as below:

enum eURL {
    projects
    }

let x:string = eURL[eURL.projects]; //x= 'projects'

However, if I use string enums as in the example below, then how can I get the string value "Help Me" from the enum?

enum myEnum {
    projects = "Help Me",
}

let x:string = myEnum[myEnum.projects]; // returns undefined.

T.J. Crowder · Accepted Answer · 2019-04-18 08:49:43Z

3

You just use it directly:

let x:string = myEnum.projects;

answered Apr 18, 2019 at 8:49

T.J. Crowder

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1 Comment

Thanks, sometimes the obvious eludes

Pavel Kratochvil · Accepted Answer · 2019-04-18 09:28:38Z

0

The reason why first example works and second not is connected to how is typescript transpiling normal enum vs string enum. Normal:

(function (myEnum) {
    myEnum[myEnum["projects"] = 0] = "projects";
})(myEnum || (myEnum = {}));

It uses index as key and also value as key and do mapping from value to index and index to value and produce object which look like this:

{0: "projects", projects: 0}

String:

(function (myEnum) {
    myEnum["projects"] = "Help Me";
})(myEnum || (myEnum = {}));

String enum on the other hand map only key to value and produce this:

{projects: 0}

answered Apr 18, 2019 at 9:28

Pavel Kratochvil

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