JS-023
Educational JavaScript lesson graphic for Decrement --: Learn how to use the -- operator to decrease a variable's value
Beginner2 min~2 min read#decrement#--#operators

Decrement --

Decrease a value by one

Goal

Learn how to use the -- operator to decrease a variable's value.

Explanation

  • The -- operator decreases a variable's value by exactly one.
  • It is shorthand for x = x - 1.
  • Decrement is often used to count lives, time, or number of attempts.
  • After the operator runs, the variable holds the new value.
  • It is one of JavaScript's basic operators.

Analogy

Imagine a game where you lose one life after each mistake. That is how the -- operator works.

Code

let lives = 3;

lives--;

console.log(lives);

Result: 2

Common mistake

You cannot write 10--. The -- operator works only with variables.

Remember

  • ✦ -- subtracts one.
  • ✦ x-- means x = x - 1.
  • ✦ Decrement works only with variables.

Quick Quiz

What value will lives have after lives-- if lives starts at 3?

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