Difference Between == and === in JavaScript

When you write code in JavaScript, one of the most common things that you do is compare values. For this, you can use the == and === operators. If you are a beginner in JavaScript programming, you may find both of these operators to be similar, but they work very differently.
In this blog, you will learn everything about the difference between the == and === operators in JavaScript, along with their use cases. So let’s get started!

Table of Contents

• Operators in JavaScript
  • Comparison Operators
• == and === Operators in JavaScript
  • == Operator in JavaScript
  • === Operator in JavaScript
• Difference between == and === Operators in JavaScript
• Best Practices for Using == and === in JavaScript
• Conclusion

Operators in JavaScript

In order to write code in JavaScript, you need to conduct various kinds of operations, such as doing some mathematics, comparing values, and determining whether something is true or false. This is where you can use operators. Operators are basically special symbols or keywords that help you to perform these actions in your code. Some of the operators in JavaScript are given below:

1. Assignment Operators: For example, =, +=, -=, *=, /=

2. Arithmetic Operators: For example, +, -, *, /, %, **

3. Comparison Operators: For example, ==, ===, !=, !==, >, <, >=, <=

4. Logical Operators: For example, &&, !

5. Bitwise Operators: &, ~, <<, >>, >>>

Comparison Operators

Comparison operators help you compare two values in JavaScript and determine whether they are greater, lesser or not equal. They provide you with the answer in the form of true or false. You can also use them in conditions such as an if statement or loops in order to make important decisions within the code. These operators can act on other varieties of data, such as numbers, strings, booleans, or even objects.

Some symbols that are used to describe the operations are:

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== and === Operators in JavaScript

Now, we will discuss the differences between the == and === operators in JavaScript and when you should use them.

== Operator in JavaScript

== Operator in JavaScript is also known as the Equality Operator. It is used to check if the two values are the same. Even if their types are different (like a number and a string), it will still return true as long as the actual values match. If the values do not match, it returns false. An example code is given below for your reference:

Code:

Output:

Explanation:

The above code is used to check if the string “10” and the number 10 are equal. It uses the == operator and returns true. This is because the string is converted to a number before they are compared.

=== Operator in JavaScript

=== Operator in JavaScript is also called the Strict Equality Operator. It checks whether both the values and the data type of the two variables are the same. If the value and data-type both match, it returns true, else false. This operator does not convert the data type like the == Operator. It compares things the way they are without converting them into the same type. An example code is given below for your reference:

Code:

Output:

Explanation:

The above code is used to check if both the value and type of each pair are the same. It uses the === operator and prints true when both data types match exactly.

Difference between == and === Operators in JavaScript

The difference between == and === Operators in JavaScript is given below in a Tabular format:

Best Practices for Using == and === in JavaScript

1. You should always use === rather than == unless you have a good reason not to.  It avoids confusing results because it checks both value and type.

2. == tries to convert the values before comparing them. This can lead to unexpected results. Using === helps you to keep things clear.

3. You should not mix == and === randomly in your code. You should pick one operator (===) and stick to it throughout your code so that your code is easily understandable.

4. If you are sure about allowing different types (like comparing null and undefined), then you can use ==. But use it carefully.

Conclusion

It is important for you to understand the difference between the == and === operators in JavaScript if you want your code to behave the way you expect. The == operator is used to compare values and also converts the data types. On the other hand,  the === operator checks both the value and the data type exactly. In most cases, it’s recommended to use the === operator so you don’t get confusing results. You need to follow all the best practices so that you can write cleaner, more reliable code and avoid common mistakes in JavaScript. If you are an aspiring web developer, explore JavaScript Interview Questions and enroll in our Web Development Course.

Difference between == and === Operators in JavaScript – FAQs