Call Method Javascript

• What is call?

  • call() is a method available on all functions
  • It allows you to invoke a function with a specified this value and individual arguments.
  • call() takes an object as first argument, & then a list for the functions arguments on which it is called upon, refer example 2

• Syntax:

  functionName.call(thisArg, arg1, arg2, ...);
  

  • functionName: The function you want to call.
  • thisArg: The value to be used as this inside the function.
  • arg1, arg2, ...: The arguments to be passed to the function.

• Example 1:

  const person = {
  	fullName: function() {
  		return this.firstName + " " + this.lastName;
  	}
  };
  
  const person1 = {
  	firstName: "John",
  	lastName: "Doe",
  };
  
  console.log(
  	person.fullName.call(person1);
  ); // Outputs: "John Doe"
  

• Example 2:

var obj = { name: "Chaitanya" };

function sayHello(age) {
	return "Hello " + this.name + " is " + age;
}

console.log(sayHello.call(obj, 22));