The addition assignment or the += operator does the addition and assignment in a single operation.

To learn how it works, let’s first try to separate the assignment and the increment.

let a = 1;

a = a + 2;

console.log(a);

Output:

3

The example above creates the variable a equal to 1 and then increments the value of it by 2.

This example can be rewritten using the += operator.

let a = 1;

a += 2;

console.log(a);

The output remains the same:

3