Increment Operators

Increment and decrement operators are a particular form of arithmetic operators: ++ and --. a++ increments a and returns the old value of a. ++a increments a and returns the new value of a. The decrement operator acts similarly but reduces the variable instead.

As an example, the next operations all perform the same task:

"use strict";
let a = 1;
alert(a);     // 1

a = a + ...