Conditional Statements in JavaScript

JavaScript provides several types of conditional statements, including if, else and ternary operators (condition ? expressionIfTrue : expressionIfFalse)

if, else

let score = 85;

if (score >= 90) {
  console.log("Grade: A");
} else if (score >= 80) {
  console.log("Grade: B");
} else if (score >= 70) {
  console.log("Grade: C");
} else {
  console.log("Grade: F");
}

The code evaluates multiple conditions in sequence. It checks if score is 90 or higher, then 80 or higher, and so on, assigning a grade based on the range the score falls into.

The Ternary Operator

The ternary operator is a shorthand way to write simple if-else statements. It is often used to assign a value to a variable based on a condition.

condition ? expressionIfTrue : expressionIfFalse

let age = 20;
let canVote = age >= 18 ? "Yes" : "No";
console.log(canVote);  // Output: Yes

The ternary operator checks if age is greater than or equal to 18. If true, it assigns "Yes" to canVote; otherwise, it assigns "No".

&& (AND) Operator

The && operator checks if both conditions are true.

let age = 25;
let hasLicense = true;

if (age >= 18 && hasLicense) {
  console.log("You can drive.");
}

The message "You can drive" is printed only if both age is 18 or older and hasLicense is true.

|| (OR) Operator

The || operator checks if at least one of the conditions is true.

let isWeekend = true;
let isHoliday = false;

if (isWeekend || isHoliday) {
  console.log("You can relax today.");
}

The message "You can relax today" is printed if either isWeekend or isHoliday is true.

`!` (NOT) Operator

The ! operator inverts a condition, making true become false and vice versa.

let isRaining = false;

if (!isRaining) {
  console.log("You don't need an umbrella.");
}

The message "You don't need an umbrella" is printed if isRaining is false (because !isRaining is true).

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