---
id: 5d792533ed00e75d129e1b18
title: Part 13
challengeType: 0
dashedName: part-13
---
# --description--
`replace` is a higher order function because it can take a function as argument (higher order functions can also return functions).
Pass the `+` function from `infixToFunction` to the `replace` method as the second argument.
This is how you would pass the `-` function:
```js
str.replace(regex, infixToFunction["-"])
```
# --hints--
See description above for instructions.
```js
assert(infixEval('ab', /(a)b/) === 'aba');
```
# --seed--
## --before-user-code--
```html
Spreadsheet
```
## --after-user-code--
```html
```
## --seed-contents--
```html
```
# --solutions--
```html
```