Simple example of how to replace the lack of enums in JS

enum-analogue.js

function* generateIds() {
	let i = 0;
	while (true) { yield i; i++ } 
}

const generator = generateIds();

const getId = () => { return Object.freeze(generator.next().value) }

const typesList = [
	`TEST`,
	`GET`,
	`BLA`
];

const typesObject = typesList.reduce((o, key) => ({ ...o, [key]: getId()}), {});

const Types = Object.freeze(typesObject);

console.log(Types.GET);

Types.GET = 15;

console.log(Types.GET);