ES6 Everyday: const Keyword
Starting off our week with one that’s pretty straightforward: the const keyword.
So, let’s say we have a constant value that we don’t want changed after assignment:
var appName = "The Fantastic Editor";
appName = "The TERRIBLE Editor";
console.log(appName); // The TERRIBLE Editor
We can use the const keyword to prevent reassignment:
const appName = "The Fantastic Editor";
appName = "The TERRIBLE Editor";
console.log(appName); // EXCEPTION: "appName is read-only"
Check it out for yourself in this ES6 Fiddle.