Expression and Statement

In JavaScript:

• Expression produces a value.
• Statement performs an action.

Expression

A valid unit of code that resolves to a value.

• Simple values: 5, "hello", true
• Variables: x, y
• Operations: x + 2, Math.max(1, 2)
• Functions stored in variables (function expressions)

Function Expression

A function assigned to a variable is a function expression.

const greet = () => {
  console.log("Hello!");
};

• Stored in a variable (var, let, or const).
• Can produce a value (the function itself) that can be passed around.
• Can be anonymous or named.

Statement (Declaration)

A complete unit of execution that performs an action but may not return a value.

• Variable declarations: let x = 5;
• Conditional statements: if(x < 4) { ... }
• Loops: for(let i=0; i<5; i++) { ... }
• Function declarations (statements)

Function Statment

A function declared using the function keyword without being assigned to a variable is a statement.

function greet() {
  console.log("Hello!");
}

• Called a function declaration.
• Executes an action when invoked.
• Does not produce a value that can be assigned.

Expressoin vs Statement

Feature	Expression	Statement
Produces Value	✅ Yes	❌ Usually no
Can be Assigned	✅ Yes	❌ No
Example	5, x + 2, const f = () => {}	let x = 5;, if(x<4){}, function f(){}