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# Homework

## JavaScript Iterators

### `.forEach() or .filter()`

Write a function named onlyEven that returns evens numbers in an array.

```
onlyEven([1,2,3,4,5,6,7]) // => [2,4,6]
```

### `.forEach() or .filter()`

* `countIntegers` – counts how many integers there are in an array

```
countIntegers([4, 2.2, 5, 6, 4.2, 8.2, 4]) // => 4
```

* Hint: Google how you can check if a number is an integer in JavaScript

### `.map()` oldie but goodie

Write a function `lengths` that accepts a single parameter as an argument, namely an array of strings. The function should return an array of numbers where each number is the length of the corresponding string. use `.map`

```
lengths(['my', 'cake', 'pudding']); // => [2,4,7]
```

### `.map()`

Write code using `.map()` to have the following input and output:

* `getSquares` – takes in an array of numbers and returns an array of their squares

```
getSquares([1, 2, 3, 4, 5]) // => [1, 4, 9, 16, 25]
```

### `.map(), .filter() & .reduce()`

1. Write an expression using array iterator methods (like filter and reduce) to compute the total value of the machines in the inventory array.

```
var inventory = [
  {type:   "machine", value: 5000},
  {type:   "machine", value:  650},
  {type:      "duck", value:   10},
  {type: "furniture", value: 1200},
  {type:   "machine", value:   77}
]
```

2. Get an array of all the machines with value over 500