Assignment operators

Learn shortcut assignments with =, +=, -=, ++ and --.

The assignment operator =

To give a variable a value, you use the = operator. It takes the value on the right and stores it in the variable on the left. For example, let score = 90; makes score hold 90.

Assignment is not one-time; you can give the same variable a new value later: score = 85;. The let keyword is used only for the first declaration, not for later updates.

Compound assignment

When you update a variable, you can avoid writing it twice by using a compound assignment operator. score += 5 means the same as score = score + 5; it is just shorter.

Likewise -=, *=, /= and %= work. Most updates end up in this compact form. Also ++ adds one and -- subtracts one.

Exercise Update the stock counter

Declare stock with an initial value of 20. Then add 5 using the += operator.

Show example solution

// Declare and update the stock variable
let stock = 20;
stock += 5;

Test yourself

What does count += 3 do?
```
let count = 10;
count += 3;
console.log(count);
```
- Adds 3 to count (becomes 13)
- Sets count to 3
- Sets count to 30
- Throws an error
Show answer

Adds 3 to count (becomes 13) — Correct. The += operator adds the right side to the current value; count becomes 10 + 3 = 13.

Increment the counter by one

let visits = 7;
visits____;
console.log(visits);

Show answer

let visits = 7;
visits++;
console.log(visits);

Match the assignment operator

=

Assign a value
+=

Add and assign
-=

Subtract and assign
++

Increment by one

Next lesson: Comparison operators

We Are Enhancing Your Experience

Cookie Preferences

Strictly Necessary Cookies

Analytical Cookies