loose-envify

What is loose-envify?

The loose-envify npm package is a fast (loose) selective process.env replacer using js-tokens instead of an AST. It is commonly used to replace process.env.NODE_ENV with a static value allowing for dead code elimination in browser bundles.

What are loose-envify's main functionalities?

Environment Variable Replacement

Replaces instances of process.env.NODE_ENV with a user-defined string, allowing conditional code to be statically evaluated and potentially removed by minifiers.

"if (process.env.NODE_ENV !== 'production') { console.log('Debug info') }"

Other packages similar to loose-envify

envify

envify is similar to loose-envify but performs a full AST analysis which makes it more accurate but slower. It replaces environment variables in the same way.

dotenv

dotenv loads environment variables from a .env file into process.env, but it does not replace them in the code during the build process like loose-envify does.

cross-env

cross-env allows you to set and use environment variables across platforms but does not replace them in the code. It's used more for setting up the environment rather than for code builds.

README

loose-envify

Fast (and loose) selective process.env replacer using js-tokens instead of an AST. Works just like envify but much faster.

Gotchas

• Doesn't handle broken syntax.
• Doesn't look inside embedded expressions in template strings.
  • this won't work:

  console.log(`the current env is ${process.env.NODE_ENV}`);
  

• Doesn't replace oddly-spaced or oddly-commented expressions.
  • this won't work:

  console.log(process./*won't*/env./*work*/NODE_ENV);
  

Usage/Options

loose-envify has the exact same interface as envify, including the CLI.

Benchmark

envify:

  $ for i in {1..5}; do node bench/bench.js 'envify'; done
  708ms
  727ms
  791ms
  719ms
  720ms

loose-envify:

  $ for i in {1..5}; do node bench/bench.js '../'; done
  51ms
  52ms
  52ms
  52ms
  52ms