JavaScript Comparison Operators - Stop Making These Common JavaScript Mistakes – Learn the Right Way to Use Comparison Operators!

1. Equality Operators (Samanata operators)

== (Equality): Ye operator do values ko compare karta hai aur agar dono ki value same hoti hain, toh true return karta hai. Agar unka type alag ho, toh JavaScript automatic type conversion karke unhe compare karta hai.

let a = "5";
let b = 5;
console.log(a == b); OUTPUT-

// true

2. Strict Equality (===)

=== (Strict Equality): Ye operator do values ko bina kisi type conversion ke compare karta hai. Matlab dono ki value aur type dono same honi chahiye.

let a = "5";
let b = 5;
console.log(a === b); // false

3. Inequality Operators

!= (Inequality): Ye operator do values ko compare karta hai aur agar dono ki value different hoti hain toh true return karta hai. Agar same hoti hain toh false return karta hai.

let a = "5";
let b = 5;
console.log(a != b); // false

4. Strict Inequality (!==)

!== (Strict Inequality): Ye operator do values ko compare karta hai bina kisi type conversion ke. Agar values ya types dono mein koi difference hota hai toh true return karta hai.

let a = "5";
let b = 5;
console.log(a !== b); // true

5. Relational Operators (Sambandh operators)

> (Greater than): Ye operator check karta hai ki kya left operand right operand se bada hai ya nahi.

let a = 10;
let b = 5;
console.log(a > b); // true

< (Less than): Ye operator check karta hai ki kya left operand right operand se chhota hai ya nahi.

let a = 5;
let b = 10;
console.log(a < b); // true

>= (Greater than or equal to): Ye operator check karta hai ki kya left operand right operand se bada ya uske barabar hai.

let a = 10;
let b = 10;
console.log(a >= b); // true

<= (Less than or equal to): Ye operator check karta hai ki kya left operand right operand se chhota ya uske barabar hai.

let a = 5;
let b = 10;
console.log(a <= b); // true

6. Special Comparison Considerations

Null and Undefined Comparison: `null` aur `undefined` ko `==` operator se compare karte waqt dono ko equal maana jaata hai. `===` se compare karte waqt ye unequal hota hai, kyunki types alag hote hain.

let a = null;
let b = undefined;
console.log(a == b);  // true
console.log(a === b); // false

NaN Comparison: `NaN` ko kisi bhi value se compare karte waqt hamesha false milta hai. Isliye `isNaN()` function ka use karte hain.

let a = NaN;
console.log(a == NaN);   // false
console.log(isNaN(a));   // true

Type Coercion in Non-Strict Comparison: `==` operator type coercion karta hai, matlab values ko compare karte waqt JavaScript unhe same type mein convert kar leta hai.

let a = "10";
let b = 10;
console.log(a == b);  // true