# reduce()

A stream operation that combines elements into one result.

## What does **reduce()** do in JavaScript?

**reduce()** — A stream operation that combines elements into one result.

```javascript
const prices = [2, 3, 4];
const total = prices.reduce((sum, price) => sum + price, 0);
```

Level: Journeyman · [More JavaScript terms at this level](https://www.ask-codey.com/glossary/subjects/javascript/journeyman)

Updated: September 27, 2026

## In other subjects

- [reduce() in Java](https://www.ask-codey.com/glossary/reduce)

Source: https://www.ask-codey.com/glossary/reduce-javascript