# How JavaScript development and production builds remove development-only checks

DevFeed: [How JavaScript development and production builds remove development-only checks](<https://devfeed.tech/articles/how-does-the-development-mode-work-36171.md>)

Original publisher: [Read original article](<https://overreacted.io/how-does-the-development-mode-work/>)

Published: 2019-08-04T00:00:00Z

Content type: tutorial

Language: en

Sources: [Dan Abramov](<https://devfeed.tech/sources/dan-abramov.md>)

Topics: [JavaScript](<https://devfeed.tech/topics/javascript.md>), [React](<https://devfeed.tech/topics/react.md>), [Webpack](<https://devfeed.tech/topics/webpack.md>), [Development](<https://devfeed.tech/topics/development.md>), [Node.js](<https://devfeed.tech/topics/node-js.md>)

Tags: [code](<https://devfeed.tech/tags/code.md>), [development](<https://devfeed.tech/tags/development.md>), [javascript](<https://devfeed.tech/tags/javascript.md>), [node-js](<https://devfeed.tech/tags/node-js.md>), [react](<https://devfeed.tech/tags/react.md>), [webpack](<https://devfeed.tech/tags/webpack.md>)

## AI overview

The article explains how JavaScript projects use different development and production builds. Development builds retain warnings and checks, while build-time constants, environment conventions, bundlers such as webpack, and minification enable dead code elimination in production.

## Source excerpt

Dead code elimination by convention.