Example
firstName: "John",
lastName: "Doe",
id: 5566,
fullName: function() {
return this.firstName + " " + this.lastName;
}
};
The this Keyword
In a function definition, this refers to the "owner" of the function.
In the example above, this is the person object that "owns" the fullName function.
In other words, this.firstName means the firstName property of this object.
JavaScript Methods
JavaScript methods are actions that can be performed on objects.
A JavaScript method is a property containing a function definition.
| Property | Value |
|---|---|
| firstName | John |
| lastName | Doe |
| age | 50 |
| eyeColor | blue |
| fullName | function() {return this.firstName + " " + this.lastName;} |
Methods are functions stored as object properties.
Accessing Object Methods
You access an object method with the following syntax:
objectName.methodName()You will typically describe fullName() as a method of the person object, and fullName as a property.
The fullName property will execute (as a function) when it is invoked with ().
This example accesses the fullName() method of a person object:
Example
If you access the fullName property, without (), it will return the function definition:
Example
Adding a Method to an Object
Adding a new method to an object is easy:
Example
return this.firstName + " " + this.lastName;
};
This example uses the toUpperCase() method of the String object, to convert a text to uppercase:
let x = message.toUpperCase();
The value of x, after execution of the code above will be:
HELLO WORLD!
Example
return (this.firstName + " " + this.lastName).toUpperCase();
};
Practice Excercise Practice now