30-seconds-of-code/blog_posts/javascript-prefix-postfix-operators.md

title, type, tags, expertise, author, cover, excerpt, firstSeen

title	type	tags	expertise	author	cover	excerpt	firstSeen
What is the difference between prefix and postfix operators?	question	javascript,math	intermediate	chalarangelo	blog_images/plant-candle.jpg	While both the prefix and postfix operators increment a value, the resulting value of the expression is very different.	2021-10-31T05:00:00-04:00

The increment operator (++) adds 1 to its operand and returns a value. Similarly, the decrement operator (--) subtracts 1 from its operand and returns a value. Both of these operators can be used either prefix (++i, --i) or postfix (i++, i--).

If used prefix, the value is incremented/decremented, and the value of the expression is the updated value.

let i = 0;    // i = 0
let j = ++i;  // i = 1, j = 1
let k = --i;  // i = 0, k = 0

If used postfix, the value is incremented/decremented, and the value of the expression is the original value.

let i = 0;    // i = 0
let j = i++;  // i = 1, j = 0
let k = i--;  // i = 0, k = 1