Simple assignment is done with the equal sign (=).
It assigns the value on the right to the variable on the left:
let num = 10;
Compound assignment is done with one of the multiplicative, additive, or bitwise-shift operators followed by an equal sign (=).
These assignments are designed as shorthand for such common situations as this:
let num = 10;
num = num + 10;
The second line of code can be replaced with a compound assignment:
let num = 10;
num += 10;
Compound-assignment operators exist for each of the major mathematical operations and a few others as well.
| Description | Operator |
|---|---|
| Multiply/assign | *= |
| Divide/assign | /= |
| Modulus/assign | %= |
| Add/assign | += |
| Subtract/assign | -= |
| Left shift/assign | <<= |
| Signed right shift/assign | >>= |
| Unsigned right shift/assign | >>>= |