awesome-cordova-plugins/scripts/build/transformers/plugin-class.ts

import * as ts from 'typescript';
import { Logger } from '../../logger';
import { convertValueToLiteral, getDecorator, getDecoratorArgs, getDecoratorName } from '../helpers';
import { transformMembers } from './members';

function transformClass(cls: any, ngcBuild?: boolean) {

  Logger.profile((ngcBuild ? '[ngc]' : '[esm]') + 'transformClass: ' + cls.name.text);

    const pluginStatics = [];
    const dec: any = getDecorator(cls);

    if (dec) {
      const pluginDecoratorArgs = getDecoratorArgs(dec);

      // add plugin decorator args as static properties of the plugin's class
      for (let prop in pluginDecoratorArgs) {
        pluginStatics.push(ts.createProperty(
          undefined,
          [ts.createToken(ts.SyntaxKind.StaticKeyword)],
          ts.createIdentifier(prop),
          undefined,
          undefined,
          convertValueToLiteral(pluginDecoratorArgs[prop])
        ));
      }
    }

    cls = ts.createClassDeclaration(
      ngcBuild && cls.decorators && cls.decorators.length? cls.decorators.filter(d => getDecoratorName(d) === 'Injectable') : undefined, // remove Plugin and Injectable decorators
      [ts.createToken(ts.SyntaxKind.ExportKeyword)],
      cls.name,
      cls.typeParameters,
      cls.heritageClauses,
      [
        ...transformMembers(cls),
        ...pluginStatics
      ]
    );

    Logger.profile((ngcBuild ? '[ngc]' : '[esm]') + 'transformClass' + cls.name.text);
    return cls;
}

function transformClasses(file: ts.SourceFile, ctx: ts.TransformationContext, ngcBuild?: boolean) {
  // console.log('Transforming file: ' + file.fileName);
  return ts.visitEachChild(file, node => {
    if (node.kind !== ts.SyntaxKind.ClassDeclaration) {
      return node;
    }

    return transformClass(node, ngcBuild);
  }, ctx);
}

export function pluginClassTransformer(ngcBuild?: boolean): ts.TransformerFactory<ts.SourceFile> {
  return (ctx: ts.TransformationContext) => {
    return tsSourceFile => {
      if (tsSourceFile.fileName.indexOf('src/@ionic-native/plugins') > -1)
        return transformClasses(tsSourceFile, ctx, ngcBuild);

      return tsSourceFile;
    }
  };
}