Parcel-transformer-codegen NPM

`parcel-transformer-codegen`

A plugin for parcel (v2) to allow bundle-time asset generation. This can be useful to work efficiently with established conventions and reduce duplication and boilerplate code.

It follows pretty much the parcel-plugin-codegen implementation.

Usage

Install the plugin:

npm i parcel-transformer-codegen --save-dev

Now in your parcel configuration file you can do:

{
  // ...
  "transformers": {
    "*.codegen": ["parcel-transformer-codegen"]
  }
}

At this point you can reference a .codegen file in any file, e.g., in a TypeScript asset

import generatedModule from './my.codegen';

Create a .codegen file with the structure:

module.exports = function() {
  return `export default function() {}`;
};

Async Generation

You can also use promises in your code generation. As an example, if your .codegen file looks similar to this:

module.exports = function() {
  return callSomeApi().then(result => `export default function() { return ${JSON.stringify(result)}; }`);
};

The new asset will be created asynchronously. Furthermore, you can obviously use require or import directly in your generated code. Since the asset will be run through parcel like any other asset, you can use this mechanism to include files from a directory without referencing them explicitly:

module.exports = function() {
  return `
    import { lazy } from 'react';
    export default lazy(() => import(${JSON.stringify(filePath)}));
  `;
};