JavaScript

This page explains how switch compares one value with several fixed choices using case, break, and default.

Goal: choose clear branches for one value and avoid accidental fall-through.

switch

Use switch when one expression should be compared with several known values. Each case names one possible value, and default handles everything else.

const day = "Monday";

switch (day) {
  case "Monday":
    console.log("Start of the week");
    break;
  case "Friday":
    console.log("Almost the weekend");
    break;
  default:
    console.log("Another day");
}

What each part does

switch (expression)

Evaluates the value to compare.

case value:

Matches a fixed value and starts that block.

break

Leaves the switch after the matching block.

default:

Runs when no case matches. It is optional.

Fall-through can be intentional

Without break, execution continues into the next case. This is called fall-through. You can use it deliberately when several values share one action, but make the intent clear.

switch (role) {
  case "admin":
  case "editor":
    console.log("May edit");
    break;
  default:
    console.log("Read only");
}

switch or if?

Use switch for one value and several fixed matches. Use if / else if for ranges, compound conditions, or comparisons such as score >= 80.

Related topics