factory pattern to create worker-like component objects or actors (eventually)

component-create.js

// 8-9 March 2023
// component.create
// factory pattern to create worker-like component objects or actors (eventually)

// no big plans for expansion, just an illustration; however,
// a couple methods trying to wriggle into the implementation include:
// 1. extend()...? maybe.
// 2. terminate() + onterminate()...? maybe.

// suppose we could turn this into a closure and track each created object
// with addresses then route all messages by address...

var component = {

  // 19 March 2023
  // TODO
  // should be create(...data) where each datum or part is an object spec
  // from which we create hybrid objects

  create(data) {

    // Clone an object from the "prototype" property.

    var o = Object.assign({}, component._);

    // Record properties to avoid overwriting them in the next step.

    var keys = Object.getOwnPropertyNames(o).reduce(function(keys, key) {
      keys[key] = key;

      return keys;
    }, {});

    Object.keys(Object(data)).forEach(function(k, i) {

      // Allow entries only if not their key is not already defined.

      !(k in keys) && (
        o[k] = data[k]
      );
    });

    return Object.freeze(o);
  },

  // not sure this makes sense yet
  extend() {
  // what will we accept
  // what will we allow to be overridden
  },

  _: {
    postMessage(data) {
      var error = Object(data) !== Object(data)
        ? `message data not compatible with structured clone, "${data}"`
        : "";

      if (error) {
        console.error(error);

        // TODO: add error dispatcher and error receiver support

        return error;
      }

      'onmessage' in this
        ? this.onmessage({ data: structuredClone(data), timestamp: Date.now() })
        : console.warn(`"onmessage function not defined"`);
    }
  }
}

var example = component.create({
  "smh": "smh",

  pwn: function() {
    var msg = "you've been pwn'd";

    console.warn(msg);

    return msg;
  },

  onmessage(message) {
    console.log(JSON.stringify(message, null, 2));
//     console.log({ component });
//     console.log({ "this": this });
  }
});

/* test it out */

console.group("unstructured data");
  example.postMessage("hi");
  // message data not compatible with structured clone, "hi"

  example.postMessage(example.smh);
  // message data not compatible with structured clone, "smh"

  example.postMessage(example.pwn());
  // you've been pwn'd
  // message data not compatible with structured clone, "you've been pwn'd"
console.groupEnd("unstructured data");

console.group("testing onmessage");
  example.onmessage("testing");
  // "testing"
console.groupEnd("testing onmessage");

console.group("default");
((empty) => {
  empty = component.create();

  console.group("missing onmessage");
    empty.postMessage("something");
    // message data not compatible with structured clone, "something"
  console.groupEnd("missing onmessage");

  console.group("frozen interface");
    empty.onmessage = function(something) {
      console.log("data:", something.data);
      console.log("timestamp:", something.timestamp);
    }

    empty.postMessage(["something"]);
    // onmessage function not defined
  console.groupEnd("frozen interface");

  console.group("patch by extending");
    // patch onmessage on the empty default component

    var patch = component.create(Object.assign({
      onmessage(something) {
        console.log("data:", something.data);
        console.log("timestamp:", something.timestamp);
      }
    }, empty));

    patch.postMessage(["something"]);
    // data: Array [ "something" ]
    // timestamp: 1678406504331
  console.groupEnd("patched onmessage");
})();
console.groupEnd("default");

console.group("extend");
((base, next) => {
  next = component.create(base);

  console.group("postMessage");
    next.postMessage({ string: "string" });
    /*
    {
      "data": {
        "string": "string"
      },
      "timestamp": 1679288659125
    }
     */
  console.groupEnd("postMessage");

  console.group("trait");
    next.onmessage = function() { throw new Error("overridden")
      console.log("next.onmessage.overridden")
    };
    next.postMessage({})
  console.groupEnd("trait");
})(example);
console.groupEnd("extend");