java.js

// We use class syntax to define our extension object

// This isn't actually necessary, but it tends to look the best

class JavaScriptScratch {

  /**

   * Scratch will call this method *once* when the extension loads.

   * This method's job is to tell Scratch things like the extension's ID, name, and what blocks it supports.

   */

  getInfo() {

    return {

      // `id` is the internal ID of the extension

      // It should never change!

      // If you choose to make an actual extension, please change this to something else.

      // Only the characters a-z and 0-9 can be used. No spaces or special characters.

      id: 'jscratch',

      // `name` is what the user sees in the toolbox

      // It can be changed without breaking projects.

      name: 'Javascript',

      blocks: [

        {

          // `opcode` is the internal ID of the block

          // It should never change!

          // It corresponds to the class method with the same name.

          opcode: 'sayfromjavascript',

          blockType: Scratch.BlockType.Stack,

          text: 'Hello!',
          
          arguments: {

            ONE: {

              type: Scratch.ArgumentType.STRING,

              defaultValue: ''

            }

        }

      ]

    };

  }

  /**

   * Corresponds to `opcode: 'hello'` above

   */

  sayfromjavascript() {

    // You can just return a value: any string, boolean, or number will work.

    // If you have to perform an asynchronous action like a request, just return a Promise.

    // The block will wait until the Promise resolves and return the resolved value.
    


    return alert(args.ONE);

  }

}

// Call Scratch.extensions.register to register your extension

// Make sure to register each extension exactly once

Scratch.extensions.register(new JavaScriptScratch());