# level-concat-iterator > Concatenate items from an iterator into an array. [![level badge][level-badge]](https://github.com/Level/awesome) [![npm](https://img.shields.io/npm/v/level-concat-iterator.svg?label=&logo=npm)](https://www.npmjs.com/package/level-concat-iterator) [![Node version](https://img.shields.io/node/v/level-concat-iterator.svg)](https://www.npmjs.com/package/level-concat-iterator) [![Travis](https://img.shields.io/travis/Level/concat-iterator.svg?logo=travis&label=)](https://travis-ci.org/Level/concat-iterator) [![Coverage Status](https://coveralls.io/repos/github/Level/concat-iterator/badge.svg)](https://coveralls.io/github/Level/concat-iterator) [![JavaScript Style Guide](https://img.shields.io/badge/code_style-standard-brightgreen.svg)](https://standardjs.com) [![npm](https://img.shields.io/npm/dm/level-concat-iterator.svg?label=dl)](https://www.npmjs.com/package/level-concat-iterator) [![Backers on Open Collective](https://opencollective.com/level/backers/badge.svg?color=orange)](#backers) [![Sponsors on Open Collective](https://opencollective.com/level/sponsors/badge.svg?color=orange)](#sponsors) ## Usage ```js var concat = require('level-concat-iterator') var level = require('level') level('DB', function (err, db) { db.put('foo', 'bar', function (err) { concat(db.iterator(), function (err, data) { console.log(data) }) }) }) ``` **If you are upgrading:** please see [`UPGRADING.md`](UPGRADING.md). ## API ### `concat(iterator, cb)` Takes an `abstract-leveldown` compatible `iterator` as first parameter and calls back with an array of keys and values. Calls back with an error if `iterator.next(cb)` or `iterator.end(cb)` errors. ## Contributing [`Level/concat-iterator`](https://github.com/Level/concat-iterator) is an **OPEN Open Source Project**. This means that: > Individuals making significant and valuable contributions are given commit-access to the project to contribute as they see fit. This project is more like an open wiki than a standard guarded open source project. See the [Contribution Guide](https://github.com/Level/community/blob/master/CONTRIBUTING.md) for more details. ## Donate To sustain [`Level`](https://github.com/Level) and its activities, become a backer or sponsor on [Open Collective](https://opencollective.com/level). Your logo or avatar will be displayed on our 28+ [GitHub repositories](https://github.com/Level), [npm](https://www.npmjs.com/) packages and (soon) [our website](http://leveldb.org). 💖 ### Backers [![Open Collective backers](https://opencollective.com/level/backers.svg?width=890)](https://opencollective.com/level) ### Sponsors [![Open Collective sponsors](https://opencollective.com/level/sponsors.svg?width=890)](https://opencollective.com/level) ## License [MIT](LICENSE.md) © 2018-present [Contributors](CONTRIBUTORS.md). [level-badge]: http://leveldb.org/img/badge.svg