JavaScript if/else Statement

JavaScript's If...Else statements are fundamental constructs that enable developers to create conditional logic, allowing the execution of different code blocks based on specified conditions. Here's a comprehensive explanation of If...Else statements with examples:

If Statement

The basic form starts with the if keyword, followed by a condition enclosed in parentheses. If the condition evaluates to true, the code block within the curly braces {} is executed.

If...Else Statement

By extending the if statement with an else clause, you can provide an alternative code block to be executed when the condition evaluates to false.

let age = 16; if (age >= 18) { console.log("You are eligible to vote."); } else { console.log("You are not eligible to vote yet."); }

If...Else If...Else Statement

To handle multiple conditions, you can use else if clauses between the initial if and the final else.

let score = 85; if (score >= 90) { console.log("You got an A."); } else if (score >= 80) { console.log("You got a B."); } else if (score >= 70) { console.log("You got a C."); } else { console.log("You need to improve your score."); }

Nested If...Else Statements

If...Else statements can be nested, allowing for more intricate conditional flows.

let time = 14; let isMorning = true; if (isMorning) { if (time < 12) { console.log("Good morning!"); } else { console.log("It's afternoon."); } } else { console.log("It's not morning."); }

Ternary Operator (Conditional Operator)

For concise conditional assignments, the ternary operator can be used as a shorthand.

let age = 20; let status = (age >= 18) ? "Adult" : "Minor"; console.log(status); // Output: "Adult"

Conclusion

If...Else statements form the backbone of decision-making in JavaScript, allowing developers to control the flow of their programs based on various conditions, ultimately enhancing the logic and interactivity of their applications.