Tutorial 02 Play with Types

Goals

In this tutorial, you are going to learn:

• How to get TypeScript support.
• How to make changes to Java types.

Steps

• Download this folder to a local folder along with your code.
• Add the following line to your JavaScript or TypeScript code to get intellisense in VS Code.

/// <reference types="../jaspiler/index.d.ts"/>

• Add the following line to your JavaScript code to get additional type support.

const { JTKind, /* You may add more exports. */ } = require('./jaspiler/jaspiler');

• Listen to Class(node) and change the Java types.

/// <reference types="../jaspiler/index.d.ts"/>

const { JTKind } = require('./jaspiler/jaspiler');

const result = jaspiler.transformSync(
  `package com.test;
  public class A {}
  public interface B {}
  public record C() {}
  public class D {}
  `,
  {
    plugins: [{
      visitor: {
        Class(node) {
          const simpleName = node.simpleName.value;
          switch (simpleName) {
            case 'A':
              node.kind = JTKind.INTERFACE;
              break;
            case 'B':
              node.kind = JTKind.CLASS;
              break;
            case 'C':
              node.kind = JTKind.ENUM;
              break;
            case 'D':
              node.kind = JTKind.RECORD;
              break;
          }
        },
      },
    }],
    sourceType: 'string',
  });
console.info(result.code);

• The output is:

package com.test;

public interface A { // class is converted to interface.
}

public class B { // interface is converted to class.
}

public enum C { // record is converted to enum.
}

public record D { // class is converted to record.
}

The complete code is at 02_play_with_types.js

Summary

• It's easy to get intellisense.
• Almost all nodes in the visitor events can be consumed and changed.