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Control Flow Logic

Conditional statements control behavior in JavaScript and determine whether or not pieces of code can run.

1. if / else if / else​

The most common way to branch logic.

const hour = 14;

if (hour < 12) {
    console.log("Good morning!");
} else if (hour < 18) {
    console.log("Good afternoon!");
} else {
    console.log("Good evening!");
}

2. Ternary Operator​

A clean shorthand for simple if/else assignments. Syntax: condition ? runIfTrue : runIfFalse

const age = 20;
const allowed = age >= 18 ? "Welcome!" : "Too young";

3. Switch Statement​

Used when you are checking the same variable against multiple possible explicit values. It is cleaner than drawing out ten else if blocks.

const role = "admin";

switch (role) {
    case "admin":
        console.log("Full Access");
        break; // Crucial! Without break, logic falls through to the next case.
    case "editor":
        console.log("Write Access");
        break;
    default:
        console.log("Read-only Access");
}