---
id: 5d79253307ecd49e030bdcd1
title: Part 23
challengeType: 0
dashedName: part-23
---
# --description--
Recursion is when a function calls itself. We often use it instead of `while`/`for` loops, as loops usually involve mutable state.
Replace the empty string in `highPrecedence` with a call to `highPrecedence` with `str2` as argument.
# --hints--
See description above for instructions.
```js
assert(
highPrecedence('2*2*2') === '8' &&
highPrecedence('2*2') === '4' &&
highPrecedence('2+2') === '2+2'
);
```
# --seed--
## --before-user-code--
```html
Spreadsheet
```
## --after-user-code--
```html
```
## --seed-contents--
```html
```
# --solutions--
```html
```