Explain invoking function in JavaScript

In this article, we will learn about invoking the function in Javascript, along with understanding its implementation through examples. Function Invoking is a process to execute the code inside the function when some argument is passed to invoke it. You can invoke a function multiple times by declaring the function only once. When the function is defined, the code inside a function will not be executed. It is common to use the term “call a function” instead of “invoke a function”. Although, there has a difference between these two terms. When you make a function call, you are directly telling the function to execute, whereas when you invoke a function, you are letting something execute the function. For instance,

functionName();

Here, we have invoked the function ie., letting it run, by calling the function directly.

Syntax:

function myFunction( var ) {
   return var;
}
myFunction( value );

Here, by calling myFunction, you are invoking value, which is being called indirectly.

Invoking a Function as a Method: We can define the function as an object method.

Syntax:

var myObject = {
   var : value,
   functionName: function () {
       return this.var;
   }
}
myObject.functionName();  

Parameters: It contains two parameters as mentioned above and described below:

• functionName: The functionName method is a function and this function belongs to the object and myObject is the owner of the function.
• this: The parameter this is the object that owns the JavaScript code and in this case the value of this is myObject.

We will understand the above concepts through examples.

Example 1: This example uses the function invocation to add two numbers.

Output:

 

Example 2: This example illustrates this keyword to point to the current object.

Output:

Full name : Steve smith