JavaScript comparison operators are your workhorses for evaluating relationships between values. They return true or false based on whether a condition holds.

Types of Comparison Operators

JavaScript offers a toolbox of comparison operators, each serving a specific purpose:

• Equality (==) - Checks if two values are equal, even performing type conversion if necessary (often leading to unexpected results).

• Strict Equality (===) - Compares both value and type, ensuring a stricter match.

• Inequality (!=) - Opposite of ==, checks if values are not equal.

• Strict Inequality (!==) - Opposite of ===, checks if values are not equal in value or type.

• Greater Than (>) - Determines if the left operand is greater than the right.

• Greater Than or Equal To (>=) - Checks if the left operand is greater than or equal to the right.

• Less Than (<) - Determines if the left operand is less than the right.

• Less Than or Equal To (<=) - Checks if the left operand is less than or equal to the right.

Understanding Type Coercion with ==

When using ==, JavaScript might convert one operand's type to match the other before comparison. This can lead to surprising behavior, so it's generally recommended to use strict comparison (===) for clarity and consistency. Here are some examples:

JavaScript

5 == '5'  // true (converts '5' to number)
0 == false // true (converts false to 0)

Strict Comparisons with === and !==

Strict comparison operators (=== and !==) avoid type coercion, ensuring a more reliable evaluation. They only return true if both value and type are identical:

JavaScript

10 === '10' // false (different types)
null === undefined // false (different types)

Special Cases: null, undefined, and NaN

These values have unique comparison behavior:

• null and undefined are loosely equal (==) but strictly unequal (!==).

• NaN is not equal to anything, including itself (NaN != NaN).

In Conclusion

By mastering JavaScript comparison operators, you'll gain the power to make informed decisions within your code. Remember to use strict comparisons (=== and !==) whenever possible to avoid unintended type conversion surprises.