# Arrow Functions

Arrow functions simplify the ** syntax** of our traditional functions.

They use symbols that make intuitive sense to help make our functions simpler.

The old way of writing functions:

```
const add = function(a, b){
return a + b;
}
```

With arrow functions, we can remove the function key word, and add an arrow comprised of `=`

and `>`

.

```
const add = (a, b) => {
return a + b;
}
```

Cool, our function is already simpler. This syntax makes sense. It's like saying "I'm going to take a and b and transform them." Right? And arrow suggests transportation, transformation, forwarding, moving, etc. "I'm going to take a and b and 'arrow' them."

But wait, there's more!!

We can simplify it some more. If your function has a single expression. Or a single line of code in the function, you can remove the curly brackets and `return`

keyword

```
const add = (a, b) => a + b;
```

This is called an implicit return.

The rule is, if you have a just one expression in your function, remove both the curly brackets ** and** the

`return`

keyword.If you only have ** one** argument, you can also drop the parentheses!

```
const double = (num) => num * 2;
```

can be written:

```
const double = num => num * 2;
```

If there are zero arguments, you need the parentheses.

```
const logHello = () => console.log("hello");
```

Arrow functions start to look especially sexy when used as anonymous callback functions.

```
const numbers = [1, 2, 3]
numbers.map(function(number) {
return 2 * number;
});
```

can be:

```
const numbers = [1, 2, 3]
numbers.map(number => 2 * number);
```

This is possible because we are using arrow functions and `.map()`

instead of a for loop.