JS If Conditions

JS Conditional

Conditional logic lets your code choose different paths based on a condition that evaluates to true or false.

let score = 75;

if (score >= 50) {
  console.log("Pass");
} else {
  console.log("Fail");
}

JS If

Use if to run code only when a condition is true.

let isLoggedIn = true;

if (isLoggedIn) {
  console.log("Welcome back!");
}

JS If Else

Use else to run an alternative block when the condition is false.

let age = 16;

if (age >= 18) {
  console.log("Adult");
} else {
  console.log("Minor");
}

Use else if when you have multiple conditions to check.

let temp = 22;

if (temp < 10) {
  console.log("Cold");
} else if (temp < 25) {
  console.log("Mild");
} else {
  console.log("Hot");
}

JS Ternary

The ternary operator is a short form of if/else for simple cases.

let points = 120;
let level = (points >= 100) ? "Pro" : "Beginner";

console.log(level);

Tip: avoid nesting ternaries; use if/else when logic grows.

JS Switch

Use switch when you compare the same value against many cases.

let day = 3;
let name;

switch (day) {
  case 1:
    name = "Monday";
    break;
  case 2:
    name = "Tuesday";
    break;
  case 3:
    name = "Wednesday";
    break;
  default:
    name = "Unknown";
}

console.log(name);

JS Booleans

A boolean is either true or false. Conditions are evaluated as booleans.

console.log(true);
console.log(false);

console.log(10 > 5);   // true
console.log(10 === 5); // false

JavaScript also has truthy and falsy values. The following are commonly falsy:

false
0
""
null
undefined
NaN

JS Logical

Logical operators combine or invert conditions: AND (&&), OR (||), NOT (!).

let hasAccount = true;
let hasPaid = false;

if (hasAccount && hasPaid) {
  console.log("Access granted");
} else {
  console.log("Access denied");
}

Use OR (||) to accept either condition.

let isAdmin = false;
let isEditor = true;

if (isAdmin || isEditor) {
  console.log("You can edit content");
}

NOT (!) flips a boolean.

let isOpen = false;

if (!isOpen) {
  console.log("Closed");
}

Next Step

Continue with JS Loops to repeat actions and work with lists of data.