Difference between `==` and `===` in JavaScript

Loose equality ==

Compares values after doing automatic type conversion.

• Performs type coercion.
• Example: 5 == "5" → true (string converted to number).
• Sometimes leads to unexpected results, e.g., 0 == false → true

Strict equality ===

Compares both value and type, with no conversion.

• No type coercion.
• Must match both value and type.
• Example: 5 === "5" → false

console.log(5 == "5");   // true  (loose equality → string coerced)
console.log(5 === "5");  // false (strict equality → type mismatch)

console.log(0 == false);  // true
console.log(0 === false); // false

console.log(null == undefined);  // true  (special case)
console.log(null === undefined); // false

Best practice: prefer === for predictable behavior.