What is JavaScript Object Literal?
JavaScript Object Literal is a non-primitive custom data type used to define objects in JavaScript. It is a JavaScript syntax for creating an object with an unordered list of key-value pairs. It is a quick and effective method for generating and storing data. This is the most popular straightforward approach to store related data as a distinct unit called object.
Table of Contents
10 Key Benefits of Using JavaScript Object Literal
- Provides a very easy syntax for object creation.
- Object literals ensure easy readability and lower maintenance of code.
- Object literals encapsulate related data and behavior.
- Object literals give us flexible and dynamic property addition and deletion.
- Object literals enhance our code’s organization and structure.
- It supports both private and public properties.
- It provides an efficient way for data manipulation and access.
- It helps developers with modular code development.
- Ensures a clean and more concise code compared to other alternatives.
- It can store almost all types of data except JS in built-in objects.
How to Use Object Literal in JS?
Object literals in JavaScript are the most popularly used custom data structures. It is used to store an object description, which is a set of comma-separated name/value pairs inside curly braces. Object literals can represent most complex entities, like object chaining, arrays, methods, computed columns, and regular expressions. It’s also used to store information about a particular object, including its state and behavior.
In object literals in JavaScript notation, an object description is written in the form of key-value pairs inside curly braces. The keys can be identifiers or strings followed by a colon. A value can be any valid JavaScript data type.
Code Sample on Object Literals in JavaScript
<script>
let advanceJS = {
name: 'Advance Javascript Course',
duration: 45,
topics: 'Namespaces, Prototypes, Generators, Chaining, javascript object literal',
faculty: 'Shawpnendu Sir'
};
</script>
Object literals can store other JS object literals and methods. For example, the following JavaScript code snippet shows how an object literal stores information about a course and holds a method that describes the detailed course curriculum:
Code Example #2
<script>
let advanceJS = {
name: 'Advance Javascript Course',
duration: 45,
topics: 'Namespaces, Prototypes, Generators, Chaining, javascript object literal',
faculty: 'Shawpnendu Sir',
detailCurriculum: function() {
return 'Day 01: ' + this.name + ' - Namespaces';
}
};
console.log(advanceJS.detailCurriculum());
</script>
Output
In JavaScript, we can use object literals to create another object. To create an another object of the object literal, you have to use the new keyword. This is called a constructor function in JS.
//AnotherOne must be a similar type class
advanceJS = new AnotherOne();
OK, so far we have created an object named “advanceJS” in our above code examples. Now we would like to check how we can access its properties and methods individually using the dot operator. So let’s start by printing each and every property of the “advanceJS” object literal:
Another Code Sample
<script>
let advanceJS = {
name: 'Advance Javascript Course',
duration: 45,
topics: 'Namespaces, Prototypes, Generators, Chaining, javascript object literal',
faculty: 'Shawpnendu Sir',
detailCurriculum: function() {
return 'Day 01: ' + this.name + ' - Namespaces';
}
};
// Accessing literal object properties
console.log(advanceJS.name);
console.log(advanceJS.duration);
console.log(advanceJS.topics);
console.log(advanceJS.faculty);
// Accessing literal object methods
console.log(advanceJS.detailCurriculum());
</script>
Output
JavaScript Object Literals Syntax Rules
Object literals strictly maintain the following syntax rules:
- The property name and value are separated by a colon.
- After each name-value pair, use a comma.
- Do not use a comma after the last name-value pair. If used, Internet Explorer will give you the error “Expected identifier, string, or number”. But Firefox won’t issue any errors.
- So it’s always best to not use a comma separator after the last property value.
JavaScript Literal Object Syntax vs. JSON Syntax
Many developers more often confused about the difference between JSON and object literal due to a very similar syntax.
Object literal syntax allow us to create a JavaScript object easily. Whereas JSON, is widely used language independent data transfer format between IT systems.
JavaScript object literal | JSON |
---|---|
It’s a JavaScript language specific object creation format. Means it is very tied to JavaScript. | It’s a language independent data transfer format. Means it is not tied only to JavaScript. |
It’s used to set and get an object data in JS. | It’s used to store data and transfer data across different IT platforms and programming languages. |
Object literals appear directly in your JS code. | JSON data always stored as a separate file with .json extension. |
Object literals do not use quotation marks in their property names. Such as: let person = { firstName: “Shawpnendu Bikash”, lastName: “Maloroy” }; | JSON property names are always inside quotation marks. Such as: { “firstName”: “Shawpnendu Bikash”, “lastName”: “Maloroy” } |
To convert a JavaScript object to JSON, use the JSON. stringify(value, replacer, space) method. | You can use JSON.parse(JSONdata) to create JavaScript object from JSON data. |
Accepted only JS specific datatypes. | JSON accepted data types are string, number, object, array, bool and null. |
Regarding number data type, you can use hexadecimal, octal. | You can use only decimal. |
Regarding string data type, you can use both single and double quotation. | You can use only double quotation. |
JS Enhanced Object Literals
It’s also necessary to mention that JavaScript object literals support a set of shorthand syntaxes, such as foo: foo assignments, generating super calls, computing properties etc.
These help us implement JavaScript literal object in very shortcut-like ways. Making our code more readable and highly manageable. And that’s why it’s called enhanced object literals in JS.
Object Literals Limitations
In JavaScript, an object literal gives us a way to create an object using very concise syntax. It allows us to make an object and enlist its properties and functions in a single declaration. It’s basically used for creating simple objects on the fly. Though it’s very handy declaration on the fly but it comes up with certain limitations also. Here we are going to list down all of its limitations.
- Object literals JS are not specially designed for creating multiple instances of similar-type objects. If you are bound to create multiple objects with the same signature, then it’s better to use a constructor function or a class to define the blueprint of your intended objects.
- Object literals JS do not provide us with better encapsulation, which means we are not able to use our specific access modifiers, like public and private properties or methods. It’s a clear violation of the OOP principle that could potentially lead to data integrity and security issues.
- Whenever you want to add multiple methods to an object literal or more complex behavior, it’s better to consider a constructor function or class instead of an object literal. Otherwise, you have to implement functions within the object, which is not a recommended practice considering code readability.
Conclusion
So from the above discussions, we understand clearly that an object literal is a JS-specific process to declare an object. There are a lot more ways to declare an object in JS. But this is the most straightforward and easy approach to dealing with objects on the fly.
FAQs
What is the meaning of “object literal” in JavaScript?
A JavaScript object declaration process contains a comma-separated definition of properties and functions.
How to create a method in object literal notation?
Look at the below code sample again:
<script>
let advanceJS = {
name: ‘Advance Javascript Course’,
duration: 45,
topics: ‘Namespaces, Prototypes, Generators, Chaining, javascript object literal’,
detailCurriculum: function() {
return ‘Day 01: ‘ + this.name + ‘ – Namespaces’;
}
};
// Accessing literal object properties
console.log(advanceJS.name);
// Accessing literal object methods
console.log(advanceJS.detailCurriculum());
</script>
What is the object literal format?
In the JavaScript object literal format, we found an object description in a set of comma-separated key-value pairs inside curly braces. The keys can be identifiers or strings followed by a colon.
What is the difference between object create and object literal?
Objects created using object literals are singletons in nature, which means when a change is made to the shorthand object, it affects the object within the whole script. Whereas if we create an object using the constructor function and make a change to it, that change does not affect the object across the script.
🏋️♂️ Discover Code Blocks From 20+ yrs JS Expert
💥 Asp.net C# Developer
🏆 Solution Architect
👨✈️ Database Administrator
📢 Speaker
🎓 MCTS since 2009
Leave a Reply