In JavaScript, operator precedence and associativity determine how expressions are evaluated when multiple operators are used together.

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🔷 1. Operator Precedence (Priority)

Precedence defines which operator is executed first in an expression.

👉 Higher precedence = executed first
👉 Lower precedence = executed later

Example:

let result = 10 + 5 * 2;

👉 Here:

• * has higher precedence than +
• So calculation is:

5 * 2 = 10
10 + 10 = 20

✅ Output: 20

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🔹 Common Precedence Order (High → Low)

Operator	Description
()	Parentheses
++ --	Increment/Decrement
* / %	Multiplication
+ -	Addition/Subtraction
< > <= >=	Comparison
== ===	Equality
&&	Logical AND
`
=	Assignment

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Example with Parentheses:

let result = (10 + 5) * 2;

👉 Parentheses override precedence:

10 + 5 = 15
15 * 2 = 30

✅ Output: 30

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🔷 2. Associativity (Direction of Evaluation)

When operators have same precedence, associativity decides left-to-right or right-to-left evaluation.

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🔹 Left-to-Right Associativity

Most operators follow this.

Example:

let result = 10 - 5 - 2;

👉 Evaluation:

10 - 5 = 5
5 - 2 = 3

✅ Output: 3

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🔹 Right-to-Left Associativity

Assignment operators follow this.

Example:

let a, b, c;
a = b = c = 10;

👉 Evaluation:

c = 10
b = 10
a = 10

✅ Output:

a = 10, b = 10, c = 10

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🔷 Combined Example

let result = 10 + 5 * 2 ** 2;

👉 Step-by-step:

1. ** → 2² = 4
2. * → 5 × 4 = 20
3. + → 10 + 20 = 30

✅ Output: 30

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🔷 Key Points to Remember

✔ Precedence = priority of operators
✔ Associativity = direction of execution
✔ Use () to control evaluation
✔ Always use parentheses for clarity in complex expressions

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🔷 Simple Trick 💡

👉 BODMAS works here too:

Brackets → Orders (powers) → Division/Multiplication → Addition/Subtraction

🔷 JavaScript Associativity Table

Operator	Description	Associativity
()	Grouping	Left → Right
[]	Array access	Left → Right
.	Object property	Left → Right
++ -- (postfix)	Increment/Decrement	Left → Right
++ -- (prefix)	Increment/Decrement	Right → Left
! ~ + - typeof	Unary operators	Right → Left
**	Exponentiation	Right → Left ⚠️
* / %	Multiplication	Left → Right
+ -	Addition/Subtraction	Left → Right
< <= > >=	Comparison	Left → Right
== != === !==	Equality	Left → Right
&&	Logical AND	Left → Right
`		`
??	Nullish Coalescing	Left → Right
?:	Ternary operator	Right → Left
=	Assignment	Right → Left
+= -= *= /=	Compound assignment	Right → Left
,	Comma operator	Left → Right

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🔷 Important Cases (Must Know)

1️⃣ Exponentiation (Right → Left)

let result = 2 ** 3 ** 2;

👉 Evaluates as:

2 ** (3 ** 2) = 2 ** 9 = 512

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2️⃣ Assignment (Right → Left)

let a, b, c;
a = b = c = 5;

👉 Works as:

c = 5 → b = 5 → a = 5

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3️⃣ Ternary Operator

let result = true ? 1 : false ? 2 : 3;

👉 Evaluates Right → Left

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🔷 Quick Memory Trick 💡

• Most operators → Left to Right
• Exceptions (Right to Left):
  • **
  • =
  • ?:
  • Unary operators (!, typeof, etc.)