discourse-bcc/assets/javascripts/discourse/initializers/setup-bcc.js

import { Result } from "discourse/adapters/rest";
import { ajax } from "discourse/lib/ajax";
import { withPluginApi } from "discourse/lib/plugin-api";

export default {
  name: "setup-bcc",
  after: "inject-objects",

  initialize(container) {
    let composer = container.factoryFor("model:composer");
    if (composer) {
      composer.class.serializeOnCreate("use_bcc");
      composer.class.serializeToDraft("use_bcc");
    }

    withPluginApi((api) => {
      api.modifyClass(
        "adapter:post",
        (Superclass) =>
          class extends Superclass {
            createRecord(store, type, args) {
              if (type === "post" && args.use_bcc) {
                return ajax("/posts/bcc", {
                  method: "POST",
                  data: args,
                }).then((json) => {
                  return new Result(json.post, json);
                });
              } else {
                delete args.use_bcc;
                return super.createRecord(store, type, args);
              }
            }
          }
      );
    });
  },
};