create function in javascript with custom prototype

Question

So I created a function like this,

var functionName = function(arg1) { //code logic here; }

At the same time, I need this function to work

Answer 1

You could set the prototype of the function.

function functionName(arg1) { 
    //code logic here;
}

var myObj = { x: 3, y: 4 };
functionName.prototype = myObj;

var obj = new functionName();
console.log(obj.x, obj.y); // will output 3, 4