Currently DiffingBroccoliPlugin provides full tree diff to plugins. This means that plugins that care about only .js or .ts files need to filter the diff themselves.

This operation is common enough that it should be implemented in the DiffingBroccoliPluginWrapper's rebuild method instead.

Proposal:

class MyPlugin implements DiffingBroccoliPlugin {
  static includeExtensions = ['.ts'];
  static excludeExtensions = ['.d.ts'];

  public rebuild(diffResult: DiffResult) {
    //diffResult contains only .ts files and no .d.ts files
  }
}

tasks:

• add filtering into DiffingBroccoliPluginWrapper
• refactor existing broccoli-typescript.ts and traceur/index.ts to rely on this feature