@adopisoft/remove-if-env

A typescript transform plugin that removes blocks of code base on Nodes.js' process.env.

Compatible with ts-patch(recommended) and ttypescript

Installation

With NPM:

npm i @adopisoft/remove-if-env --save-dev

OR with YARN:

yarn add @adopisoft/remove-if-env -D

Usage

./tsconfig.json

{
  "compilerOptions": {
    "plugins": [
      {
        "transform": "@adopisoft/remove-if-env",
        "envVar": "removeIfEnv"
      }
    ]
  }
}

./sample-source.ts

// NOTE: This variable name 'removeIfEnv' must match the value of plugin option 'envVar'.
// Please also see the section about creating the './remove-if-env.ts' file below.
import removeIfEnv from './remove-if-env'

if (removeIfEnv.PROD) {
  console.log(
    'This code block executes in development but will be striped out \
      when compiling with PROD=true tsc'
  )
}

Creating the remove-if-env.ts file

The remove-if-env.ts file is used for your local typescript completion only and to make sure the codes inside the if statement can execute locally. To do this, we have to create this file which contains placeholder values for the process.env.* properties:

./remove-if-env.ts

export default {
  PROD: true,
  SOME_OTHER_ENV: true
}

Plugin Options

envVar - Set the variable name of removeIfEnv object to be used in your codes. If not set, default is removeIfEnv. Your code must use this variable name when importing remove-if-env.ts file.

Compiling Your Code

To strip off the if statement blocks during compilation, we must set the environment variables to one of the following values - 1, yes, or true.

$ export PROD=1
$ npx tsc

Caveats

For now, the import removeIfEnv from ./remove-if-env import statement will not be stripped off in production and will remain as an unused variable in the file output.

This can be fixed by using additional javascript preprocessors like babel, terser or gulp. But the long term solution for this would be to remove the import statement in the AST within the transform plugin itself.

Project Status

This project is very much still a WIP altough this is enough for our internal tooling requirements. We will follow proper semantic versioning to avoid breaking changes for other consumers. PRs are always welcome if you want to improve this tool.

License

MIT LICENSE