The Difference Between Postfix and Prefix Increment

The increment operator in JavaScript is used for incrementing a value by 1. It has two different syntaxes, but both of them are used for incrementing a value by 1. The question is: What they will be evaluated to?

• i++, called postfix increment will evaluate to the value before it was incremented.
• ++i, called the prefix increment will evaluate to the value after it was incremented.

let i = 0;

i++ // Will evaluate to 0
++i // Will evaluate to 1

You can also do the same thing with a decrement operator. The behavior is exactly the same.

let i = 0;

i-- // Will evaluate to 0
--i // Will evaluate to -1

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Resources:

• The increment operator in JavaScript
• The decrement operator in JavaScript