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Closure Library to ES6 Converter

This project is a converter that allows to convert ES5 style Javascript classes, which use Closure goog.require/goog.provide/goog.module style, to ES6 code which uses ES6 Modules.

The main porpuse is to convert the Google Closure Library. However with a bit of customization you may also convert your own Closure style code. The result of running the converter on the closure Library can be found on GitHub and npm.

Note that we will only accept pull requests for this converter NOT for ts-closure-library itself as it is completely generated from this converter.

How the Converter works

This repository contains a submodule, which is a fork of the Closure Library with some manual fixes needed to successfully convert it.

  • Extract and index the dependency graphy of the Closure Library. (ReaderPass)
  • A subgraph that is actually used in our application (will differ for yours) is selected with all its transitive dependencies. The used namespaces are stored in required-namespaces.txt (SelectionPass)
  • A bunch a of regex replace operations is applied to the js files to make the input easier to convert (SpecificFixesApplier)
  • Cyclic dependencies are removed by merging some files into one (CyclicDependencyRemovalPass)
  • ES5 prototype based "classes" are converted to real ES6 classes (Es6ClassConversionPass)
  • Refresh the dependency graph based on the cyclic dependency removal pass (ReaderPass)
  • goog.require/goog.module are converted to ES6 imports (ConvertingPass)
  • Create a copy of the converted files and apply some fixes so that the Typescript compiler will acept them as input (SpecificFixesApplierForDeclaration)
  • Run the Typescript compiler to generate .d.ts files for the js files
  • Apply some regex replace fixes to the d.ts files (DeclarationFixer)
  • Run the Closure compiler on the generated output to ensure the js code is valid

How to run the Converter

  • Run yarn install to download Typescript
  • Ensure you have Java 11 installed and JAVA_HOME points to it
  • Run cd es6-module-converter && ./gradlew run