What Is the Difference Between ‘==’ And ‘===’ Operators in JavaScript?

JavaScript is the popular programming language allowing website developers to create and develop web site pages and applications. It gives enough freedom to make the website more interactive and dynamic. Data can manipulate, calculated, and validate with the help of JavaScript. JavaScript also has operators similar to other languages.

The operator produces the result by performing the specific action on single or multiple operands. In JavaScript, you will find various operators such as arithmetic operators, special operators, comparison operators, logical operators, and assignment operators.

These operators are accessed to perform specific mathematical and logical computations on operands. In other words, the operator will operate the operands. Operators are accessed for comparing values and performing arithmetic operations in JavaScript.

But, the JavaScript comparison operators are widely accessed to compare two operators. In general, == and === operators are the most commonly used. Keep reading to know in-depth about these operators.

What is == operator?

The == sign (double equals) function is called the equality operator. Its function is to compare two expressions or values. If the expressions are equivalent, then the result is true. Or else, the result is false. However, functions, variables, arrays, and objects are compared with the help of reference. For instance, two variables are equal when referring to a similar array, function or object.

Example

var num1=10;

var num2=5;

alert(num1==num2);

In the above example, two variables assign with the numbers 10 and 5. Then, it checks whether num1 and num2 are equal. When the double equals check by value, it results in a false statement. If both the number values are equal to 10, it returns the true value.

What is === operator?

The == sign (triple equals) is called equality operator. Its function is to check whether or not two operands are equal and return the true or false value. The operator returns false whenever the values are not of a similar type. Conversely, the operator returns true when the values are of a similar type.

Example

var num1=10;

var str1=”10″;

alert(num1===str1);

As discussed earlier, the operator checks both the type and value of two operands. Whether num1 and num2 are equal or not, it returns the false because the values are the same, but the type is not the same. It is because one is an integer, and the other is a string.

Difference between == and === in JavaScript

Since JavaScript supports strict equality and type-converting equality, it is vital to know which operator to use for the specific operation. As mentioned above, === considers the type of variable, whereas == makes the type correction according to the values of variables. Look at below to know a couple of differences between == and === operators in JavaScript.

• When comparing two variables of different types, such as a number with the string or boolean with the string using == operator, it converts one type into another. It then returns a value based on the content quality automatically. Conversely, the === operator is a strict equality operator in JavaScript and returns true if both variables are of the same type and contain the same value. You will understand it with the following example in JavaScript.

• When comparing variables using the strict equality operator in JavaScript, two objects are equal if both are of a similar type and refer to the same instance. Likewise, two strings are equal to each other when the contents of each other are the same. Are you thinking about what is the result of comparing null and undefined using == and === operator? Well, the answer is simple. If you use the == operator, then it will return true. On the other hand, when you use the === operator, it will return false.

• == operator is called a type coercion operation. As long as both values are the same and compared using == operator, the type coercion will happen. On the other side, === is called the strictly equal operator. It is much similar to the equality operator in Java. It renders the compilation error when comparing two variables whose types are not equal.

Key differences between == and === operator

Here are the significant aspects in which double equals are different from triple equals.

NamingDouble equals: It is named as the equality operator

Triple equals: It is called the strict equality or identity operator

• Syntax

Double equals: (a==b)

Triple equals: (a===b)

• Comparison

Double equals: It accessed as the type converting the conversion.

Triple equals: It is utilized as strict conversion without performing conversion in operands.

• Implementation

Double equals: It converts the operands into the same type and then compares. It means comparison will perform once both operands are of the same type.

Triple equals: It does not perform any type of conversion before comparison and returns true if both operands’ value and type are the same.

Which is faster and provides the best performance == or ===?

In theory, when comparing the variables with identical types, the performance will be the same across both operators. It is because both operators access the same algorithm. On the other hand, when the types are different, the triple equals operator performs much better than double equals as it does not do the extra step of type coercion.

However, you can do some performance tests to know the accurate result. Unless you do not need == operator, you should not use the double equals operator because it may provide you with unexpected results. In short, try to use === operator all the time and everywhere except if you need type coercion.

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