Conditionally initializing a constant in Javascript

Question

ES6 onwards we have const.

This is not allowed:

const x; //declare first
//and then initialize it
if(condition) x = 5;
else x = 10;
         


        

Answer 1

I suggest this solution with a Singleton Pattern implementation:

var Singleton = (function () {
    var instance;

    function createInstance() {
        // all your logic here
        // so based on your example:
        // if(condition) return 5;
        // else return 10;
    }

    return {
        getInstance: function () {
            if (!instance) {
                instance = createInstance();
            }
            return instance;
        }
    };
})();

const x = Singleton.getInstance();