Explain usage of NODE_ENV

Node encourages the convention of using a variable called NODE_ENV to flag whether we’re in production right now. This determination allows components to provide better diagnostics during development, for example by disabling caching or emitting verbose log statements. Setting NODE_ENV to production makes your application 3 times faster.

// Setting environment variables in bash before starting the node process
$ NODE_ENV=development
$ node

// Reading the environment variable using code
if (process.env.NODE_ENV === “production”)
    useCaching = true;