---
id: 5d79253685fc69b8fe60a0d2
title: Part 72
challengeType: 0
isHidden: true
---
## Description
Chain the `map` method to `rangeFromString(n1, n2)` and pass it `addChars(c1)(c2)` as an argument.
This returns an `addChars` function, which has `c1` and `c2` (the characters) preset, and only needs a number (`n`) to be passed to it (which we get from the `rangeFromString` array).
## Instructions
## Tests
```yml
tests:
- text: See description above for instructions.
testString: assert(code.replace(/\s/g, "").includes('constvarRangeExpanded=x.replace(rangeRegex,(match,c1,n1,c2,n2)=>rangeFromString(n1,n2).map(addChars(c1)(c2)))'));
```
## Challenge Seed
```html
```
### Before Test
### After Test
```html
```
## Solution