Add string keyword to enum declaration to automatically generate identical key/values for the enum

[dfoverdx]

Search Terms

• string enum
• #feature-request tag (both open and closed)

Suggestion

Many of our enums use identical strings and values. In fact, my team never uses numeric enums (and I do only rarely). It would be nice if there was a shortcut for this behavior.

Use Cases

I'd use this whenever I make an enum with identical keys and string values.

Examples

Current required syntax

enum ThingType {
  Type1 = "Type1",
  Type2 = "Type2",
}

const enum ConstType {
  Type1 = 'Type1',
  Type2 = 'Type2',
}

const type1 = ConstType.Type1;
const type2 = ConstType.Type2;

enum OverrideType {
  Type1 = 'Type1',
  Type2 = 'OverrideString',
  Type3 = 'Type3',
}

JavaScript output

var ThingType;
(function (ThingType) {
    ThingType["Type1"] = "Type1";
    ThingType["Type2"] = "Type2";
})(ThingType || (ThingType = {}));
const type1 = "Type1" /* Type1 */;
const type2 = "Type2" /* Type2 */;
var OverrideType;
(function (OverrideType) {
    OverrideType["Type1"] = "Type1";
    OverrideType["Type2"] = "OverrideString";
    OverrideType["Type3"] = "Type3";
})(OverrideType || (OverrideType = {}));

Desired syntax

string enum ThingType {
  Type1,
  Type2,
}

const string enum ConstType {
  Type1,
  Type2,
}

const type1 = ConstType.Type1;
const type2 = ConstType.Type2;

string enum OverrideType {
  Type1,
  Type2 = 'OverrideString',
  Type3,
}

Expected JavaScript output (identical)

var ThingType;
(function (ThingType) {
    ThingType["Type1"] = "Type1";
    ThingType["Type2"] = "Type2";
})(ThingType || (ThingType = {}));
const type1 = "Type1" /* Type1 */;
const type2 = "Type2" /* Type2 */;
var OverrideType;
(function (OverrideType) {
    OverrideType["Type1"] = "Type1";
    OverrideType["Type2"] = "OverrideString";
    OverrideType["Type3"] = "Type3";
})(OverrideType || (OverrideType = {}));

Checklist

My suggestion meets these guidelines:

• This wouldn't be a breaking change in existing TypeScript/JavaScript code
  I'm pretty sure this syntax pattern is still available.
• This wouldn't change the runtime behavior of existing JavaScript code
• This could be implemented without emitting different JS based on the types of the expressions
• This isn't a runtime feature (e.g. library functionality, non-ECMAScript syntax with JavaScript output, etc.)
• This feature would agree with the rest of TypeScript's Design Goals.

[IllusionMH]

Looks like duplicate of #16464

[typescript-bot]

This issue has been marked as a 'Duplicate' and has seen no recent activity. It has been automatically closed for house-keeping purposes.