Difference between equals sign (=) and double equals sign (==) in JavaScript?
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Equals Sign (=):
-
The equals sign (
=
) is the assignment operator in JavaScript. It is used to assign a value to a variable. For example:
var x = 5; // Assigns the value 5 to the variable x
2.It does not perform any comparison between values. Instead, it takes the value on the right-hand side and assigns it to the variable on the left-hand side.
Double Equals Sign (==):
-
The double equals sign (
==
) is the equality operator in JavaScript. It is used for comparison, specifically to check if two values are equal in terms of their content. For example:
5 == '5'; // Returns true because the values are considered equal
-
The equality operator performs type coercion, which means it can compare values of different data types and convert them if necessary to make the comparison. In the example above, the number
5
is converted to a string to perform the comparison. -
It is important to note that the equality operator may lead to unexpected results due to type coercion. For this reason, it is generally recommended to use the triple equals sign (
===
) for strict equality comparison, which checks both value and data type, without performing type coercion.
Triple Equals Sign (===):
-
The triple equals sign (
===
) is the strict equality operator in JavaScript. It is used for comparison and checks if two values are equal in both content and data type. For example:
5 === 5; // Returns true
5 === '5'; // Returns false because the values are of different data types
2.Unlike the double equals sign, the strict equality operator does not perform type coercion. It requires both the value and the data type to match for the comparison to return true
.
In summary, the equals sign (=
) is used for variable assignment, while the double equals sign (==
) and the triple equals sign (===
) are used for value comparison. The double equals sign performs type coercion and compares values, while the triple equals sign checks both values and data types for strict equality. It's generally recommended to use the strict equality operator (===
) to avoid unexpected results caused by type coercion.
Categories: Java Script Tags: #ES6, #JavaScript,