Comparison: ==, ===, !=, !==, <, >, <=, >=

1. Equality Operators

These operators check if two values are equal. This is where type coercion becomes very important.

a. Loose Equality (==)

• Compares two values for equality after performing type coercion if their types are different.
• Avoid using == in most cases as it can lead to unexpected behavior due to implicit type conversions.

Examples:

b. Strict Equality (===)

• Compares two values for equality without performing any type coercion.
• It checks both the value AND the type. If the types are different, it immediately returns false.
• Always prefer === over == for predictable and reliable comparisons.

Examples:

2. Inequality Operators

These operators check if two values are not equal.

a. Loose Inequality (!=)

• Returns true if the values are not equal after type coercion. It's the opposite of ==.
• Avoid using != for the same reasons you avoid ==.

Examples:

b. Strict Inequality (!==)

• Returns true if the values are not equal without performing any type coercion. It checks both value and type. It's the opposite of ===.
• Always prefer !== over !=.

Examples:

3. Relational Operators

These operators compare the order or magnitude of two values.

• Greater Than (>): Returns true if the left operand is greater than the right operand.
• Less Than (<): Returns true if the left operand is less than the right operand.
• Greater Than or Equal To (>=): Returns true if the left operand is greater than or equal to the right operand.
• Less Than or Equal To (<=): Returns true if the left operand is less than or equal to the right operand.

Examples:

Important Note on String Comparisons: When comparing strings with relational operators (<, >, <=, >=), JavaScript compares them lexicographically (alphabetically, based on their Unicode character values). This can lead to non-intuitive results if you're expecting numeric comparison (e.g., "20" > "100" is true). Always convert strings to numbers before comparing them numerically (e.g., using Number(), parseInt(), or parseFloat()).

Exercise: Comparison Challenges

In the editor below, write console.log() statements to output the result of each comparison. Pay close attention to strict vs. loose equality!