exenv

exenv

React's ExecutionEnvironment module extracted for use in other packages & components.

Usage

npm install exenv --save

var ExecutionEnvironment = require('exenv');

// You now have...
ExecutionEnvironment.canUseDOM             // is the DOM available? i.e window document etc. 
ExecutionEnvironment.canUseWorkers         // are Web Workers available?
ExecutionEnvironment.canUseEventListeners  // are Events available? i.e addEventListener etc.
ExecutionEnvironment.canUseViewport        // is there a viewport? i.e window.screen

Differences from React's ExecutionEnvironment

The ExecutionEnvironment lib in React 0.13 includes an isInWorker property, which is !canUseDOM. This is highly specific to React internals and probably (a) hacky and (b) not useful to other packages, so it has been left out. Please open an issue with your thoughts if you disagree or have a better idea.

Why?

A number of packages and components use React's private ExecutionEnvironment lib to detect available features, particularly to detect server-side rendering, e.g

canUseDOM = require('react/lib/ExecutionEnvironment').canUseDOM; // BAD

It is bad practice to use React internals and this is likely to be broken / disabled in the future.

Use this package instead!

Similar packages

Other packages similar to exenv

envify

Envify is a package that replaces environment variables in your code during the build step with Browserify. It is similar to exenv in that it helps manage environment-specific code, but it does so by compiling time replacements rather than runtime checks.

dotenv

Dotenv is a module that loads environment variables from a .env file into process.env. While it serves a different purpose from exenv by managing environment variables, it similarly aids in configuring different behaviors based on the environment.