botbuilder-formflow/src/custom/MenuDialog.js

Form flow with subdialogs

const matchItem = require('../matchItem');
const formFlowConsts = require('../consts');
const MenuPrompt = require('./MenuPrompt');

const botbuilder = require('botbuilder');
function MenuDialog(config) {
  this.type = 'dialog';
  this.bot = null;
  this.dialog = [];
  this.resolvedItems = null;
  for (var key in config) {
    if (config.hasOwnProperty(key)) {
      this[key] = config[key];
    }
  }
  if (!config.items) {
    throw ('Failed to instantinate MenuDialog - property "items" undefined!')
  }
}

MenuDialog.prototype.initialize = function (bot, dialogId, config) {
  config = Object.assign({}, config);
  let promptDialogId = 'MenuPrompt_' + dialogId;
  bot.dialog(promptDialogId, new MenuPrompt());
  this.dialog = [
    (session) => {
      this.resolveItems(config, session)
        .then((items) => {
          config.items = items;
          if (this.isEmptyItems(items)) {
            session.endDialog();
          }
          if (!config.retryPrompt) {
            config.retryPrompt = config.prompt;
          }
          session.beginDialog(promptDialogId, config);
        })
        .catch((error) => {
          session.logger.log(session.dialogStack(), error);
          session.send(botbuilder.Prompt.gettext(session, 'default_error', formFlowConsts.SYSTEM_NAMESPACE));
          session.endConversation();
        })

    },
    (session, args) => {
      session.beginDialog(args.response);
    },
    (session, args) => {
      session.endDialogWithResult(args);
    }
  ];


}
MenuDialog.prototype.isEmptyItems = function (items) {
  for (let key in items) {
    if (items.hasOwnProperty(key)) {
      return false;
    }
  }
  return true;
}
MenuDialog.prototype.resolveItems = function (options, session) {
  if (this.resolvedItems != null) {
    return Promise.resolve(this.resolvedItems);
  }
  let promise = null;
  if ("undefined" == typeof options.items) {
    throw new Error("MenuPrompt.items mandatory attribute")
  }
  if ("function" == typeof options.items) {
    promise = options.items.call(null, session);
    if (!(promise instanceof Promise)) {
      throw new Error("MenuPrompt.items callback must return a Promise");
    }
  } else {
    promise = Promise.resolve(options.items)
  }
  return promise;
}
MenuDialog.factory = function (bot, id, stepConfig, steps) {
  if (matchItem(stepConfig, 'menu-dialog', () => true)) {
    let dialog = new MenuDialog(stepConfig);
    dialog.initialize(bot, id, stepConfig);
    dialog.dialog.forEach((item)=>steps.push(item));
  } else if (stepConfig instanceof MenuDialog) {
    stepConfig.initialize(bot, id, stepConfig);
    stepConfig.dialog.forEach((item) => steps.push(item));
  }
}
module.exports = MenuDialog;