freeCodeCamp/curriculum/challenges/english/02-javascript-algorithms-and-data-structures/basic-data-structures/copy-an-array-with-the-spread-operator.md

---
id: 587d7b7b367417b2b2512b13
title: Copy an Array with the Spread Operator
challengeType: 1
forumTopicId: 301157
dashedName: copy-an-array-with-the-spread-operator
---

# --description--

While `slice()` allows us to be selective about what elements of an array to copy, among several other useful tasks, ES6's new <dfn>spread operator</dfn> allows us to easily copy *all* of an array's elements, in order, with a simple and highly readable syntax. The spread syntax simply looks like this: `...`

In practice, we can use the spread operator to copy an array like so:

```js
let thisArray = [true, true, undefined, false, null];
let thatArray = [...thisArray];
```

`thatArray` equals `[true, true, undefined, false, null]`. `thisArray` remains unchanged and `thatArray` contains the same elements as `thisArray`.

# --instructions--

We have defined a function, `copyMachine` which takes `arr` (an array) and `num` (a number) as arguments. The function is supposed to return a new array made up of `num` copies of `arr`. We have done most of the work for you, but it doesn't work quite right yet. Modify the function using spread syntax so that it works correctly (hint: another method we have already covered might come in handy here!).

# --hints--

`copyMachine([true, false, true], 2)` should return `[[true, false, true], [true, false, true]]`

```js
assert.deepEqual(copyMachine([true, false, true], 2), [
  [true, false, true],
  [true, false, true]
]);
```

`copyMachine([1, 2, 3], 5)` should return `[[1, 2, 3], [1, 2, 3], [1, 2, 3], [1, 2, 3], [1, 2, 3]]`

```js
assert.deepEqual(copyMachine([1, 2, 3], 5), [
  [1, 2, 3],
  [1, 2, 3],
  [1, 2, 3],
  [1, 2, 3],
  [1, 2, 3]
]);
```

`copyMachine([true, true, null], 1)` should return `[[true, true, null]]`

```js
assert.deepEqual(copyMachine([true, true, null], 1), [[true, true, null]]);
```

`copyMachine(["it works"], 3)` should return `[["it works"], ["it works"], ["it works"]]`

```js
assert.deepEqual(copyMachine(['it works'], 3), [
  ['it works'],
  ['it works'],
  ['it works']
]);
```

The `copyMachine` function should utilize the `spread operator` with array `arr`

```js
assert(code.match(/\.\.\.arr/));
```

# --seed--

## --seed-contents--

```js
function copyMachine(arr, num) {
  let newArr = [];
  while (num >= 1) {
    // Only change code below this line

    // Only change code above this line
    num--;
  }
  return newArr;
}

console.log(copyMachine([true, false, true], 2));
```

# --solutions--

```js
function copyMachine(arr,num){
    let newArr=[];
    while(num >=1){
    newArr.push([...arr]);
    num--;
    }
    return newArr;
}
console.log(copyMachine([true, false, true], 2));
```