[Feature] make generated codes from enum could be minified when not used

Search Terms

For now TypeScript will transform enum from

enum Test {
    Key = 1
}

to

var Test;
(function (Test) {
    Test[Test["Key"] = 1] = "Key";
})(Test || (Test = {}));

This result is not friendly for uglyify or tree-shaking.
When Test is not be used, the generated code block always remain as dead codes.

Suggestion

prefer to generate codes below:

var Test = /*#__PURE__*/(function () {
    var e = {}
    e[e["Key"] = 1] = "Key";
    return e
})();

Examples

The suggestion version will be removed.

Checklist

My suggestion meets these guidelines:

• This wouldn't be a breaking change in existing TypeScript / JavaScript code
• 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. new expression-level syntax)

Aucun fichier source, test ou point d’entrée n’est indiqué. Commencez par localiser l’enum emitter de TypeScript et les tests existants de sortie d’enum, puis comparez la forme émise au comportement du minifier et du tree-shaking. C’est terminé lorsqu’une stratégie d’émission approuvée est couverte par des tests de régression sans modifier le comportement à l’exécution.