@travetto/transformer

travetto: Transform

Install: primary

$ npm install @travetto/transformer

This module provides support for enhanced AST transformations, and transformer registration, with support for common AST transformation patterns to facilitate all the transformers used throughout the framework. Transformations are defined by support/transformer.<name>.ts as the filename. The schema for a transformer is:

Code: Sample transformer, registration and execution

  export class CustomerTransformer {
    after: ['base'],
    phase: 'before'|'after', // The phase as defined by Typescript's AST processing
    transformer: (context: ts.TransformationContext) => {
       return (file: ts.SourceFile) => {
         ... modify source file ...
         return file;
       }
    }
  }

Advanced

When dealing with transformers, logging is somewhat tricky as the compiler executes before the code is loaded. To that end, a file compiler.log is created in the cache directory during the compilation process. This is a location that transformers should be free to log to, for debugging, and any additional feedback.