I was trying the below commands on Chrome console. I am able to create the object using new(line 2 below) but using call doesn't work. Can anyone explain what could be the reason ?
function ObjConstructor(){ this.sample = 1};
let withNew = new ObjConstructor();
let usingCall = ObjConstructor.call({});
usingCall
undefined //output that came on console, this is not a command
withNew
ObjConstructor {sample: 1} //output that came on console
new does several things including:
this value to that objectYour code:
{}this value to that object with call()… but doesn't do the last thing. There is no return statement in the function, so it returns undefined.
The result of call is whatever the function returns. Your ObjConstructor doesn't return anything, so the result of calling it is undefined.
In contrast, when you use new, a new object is created and passed to the function, and unless the function returns a non-null object, the object created for new is the result of the new expression.
That's why the new version works but the call doesn't.
Also note that call doesn't create an object at all. In your ObjConstructor.call({}), what creates the object is {}, not call. It won't have ObjConstructor.prototype as its prototype. ({} is a raw object initializer, so the object will have Object.prototype as its prototype.)
try this. Or look at this -> https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Working_with_Objects
var MyType = function(_param1,_param2){
this.param1 = _param1;
this.param2 = _param2;
this.ShowParam = function(){
alert(this.param1+" - "+this.param2);
}
}
var test = new MyType("PARAM TEST 1","PARAM TEST 2");
alert(test.param1+" - "+test.param2);
var test2 = new MyType("PARAM TEST 1.2","PARAM TEST 2.2");
alert(test2.param1+" - "+test2.param2);
test.ShowParam();
test2.ShowParam();
