Minion Callbacks

Learning Objectives

Getting comfortable with array methods that use callbacks

Prerequisites

JavaScript (Functions, callbacks, array methods)

Setup

Create a new file called minions.js and place your code in there.

Messing with the minions

With the given array of minions...

const minions = [
  "bob",
  "kevin",
  "stuart",
  "dave",
  "jerry",
  "mark",
  "tim",
  "phil",
  "carl",
]

Gru, the mob boss, wants to test out some array methods with callbacks. Let's go ahead and help him out.

forEach

First, he wants to test out forEach to check who's present. So as he goes down the array of minions, they should console.log that they're here.

Expected output:

```js bob - here kevin - here stuart - here // and so on and so forth all the way down to carl ```

### map

They're all here -- great! But Gru has noticed something off about the array of minions: their names aren't capitalized. He might be a mob boss, but he does care about correct grammar! So let's go ahead and fix that for him using the map method.

Using the map method, capitalize each minion's name EXCEPT kevin's because he was being sneaky and save it to a new array called capitalizedMinions

Expected output:

Bob
kevin
Stuart
// and so on and so forth all the way down to Carl

filter

Uh oh! Not every minion was capitalized. Gru's not feeling too happy about that, so now he wants to test out the filter method to filter out the sneaky minion who didn't get capitalized.

Use filter to filter out minions that are not capitalized and save the correctly capitalized minions to an array called actuallyCapitalizedMinions

Expected output:

// if you console.log actuallyCapitalizedMinions, kevin should be gone and you should see..
Bob
Stuart
Dave
// and so on and so forth all the way down to Carl

Use every again, but this time on your new actuallyCapitalizedMinions array, to check if they're all capitalized now
- Expected output:
```
true
```

BONUS METHODS

every

In order to check whether or not that previous map worked, Gru wants to try using the every method instead. So, using every, check whether or not every minion in capitalizedMinions are actually capitalized.

Create a function called isCapitalized that accepts a minion as an argument and checks whether or not the first letter of the minion's name is capitalized
Now using both the every method and the isCapitalized method you just wrote, check whether or not all the capitalizedMinions are capitalized
Expected output:
```
false
```

find

Great! We filtered out the non-capitalized minion, but while we know it was kevin, Gru didn't know that. So, he wants to find out which minion escaped his map earlier by testing out the find method.

Using find, find which minion is not correctly capitalized in the original capitalizedMinions array and save it to a variable called uncapitalizedMinion, then console log it
Expected output:
```
kevin
```

findIndex

Aha! Now that Gru's found out which minion escaped him, he wants to find out what index in the original array he was at so he can fix him up later.

Using findIndex, find what index kevin is in the original capitalizedMinions array
- Expected output:
```
1
```
Now that he's found him, he can just use capitalizedMinions[1] to select kevin and capitalize his name.
Once that's done, check again using every whether or not capitalizedMinions is all capitalized correctly
- Example output:
```
true
```

reduce

Sweet! Now that that's all sorted, Gru can just have some fun testing out the remaining array methods he wanted to learn, starting with reduce. Out of curiority, he wants to know what the sum of all his minions' name lengths is. Use reduce to find out

First, using map create a separate array called minionNameLengths that maps out the minions' name lengths
- Expected output:
```
// if you console logged minionNameLengths, you should get
[ 3, 5, 6, 4, 5, 5, 4, 3, 4, 4 ]
```
Use reduce to sum up the minionNameLengths array
- Expected output:
```
// the sum should be 38
```

some

Now Gru wants to test out the some method, so let's go ahead and do that a few times.

Check whether or not some of the minion's name lengths are 6 or above. How about 7 or above?
Lowercase Kevin's name again inside of the capitalizedMinions array, then check whether or not some of the minion's names are capitalized using some. How about it any are lowercased?

sort

Great, now Gru has had some practice with array methods that require callbacks. Now it's time to do some bad guy stuff. Before he can do so by sending his minions out to do his bidding, he wants to sort them in ascending order of their name lengths. Because why not?

Use sort to order the minions within the capitalizedMinions array by order of name length.
Hints: you'll need to write your own compareMinions function first to pass in as a callback to sort

Expected output:

// if you console log capitalizedMinions after sorting, you should get
;["Bob", "Tim", "Dave", "Mark", "Phil", "Carl", "kevin", "Jerry", "Stuart"]