Class SkillShareApp

code/solutions/21_2_comment_field_resets.mjs:41–76

}

class SkillShareApp {
  constructor(state, dispatch) {
    this.dispatch = dispatch;
    this.talkDOM = elt("div", {className: "talks"});
    this.talkMap = Object.create(null);
    this.dom = elt("div", null,
                   renderUserField(state.user, dispatch),
                   this.talkDOM,
                   renderTalkForm(dispatch));
    this.syncState(state);
  }

  syncState(state) {
    if (state.talks == this.talks) return;
    this.talks = state.talks;

    for (let talk of state.talks) {
      let found = this.talkMap[talk.title];
      if (found && found.talk.presenter == talk.presenter &&
          found.talk.summary == talk.summary) {
        found.syncState(talk);
      } else {
        if (found) found.dom.remove();
        found = new Talk(talk, this.dispatch);
        this.talkMap[talk.title] = found;
        this.talkDOM.appendChild(found.dom);
      }
    }
    for (let title of Object.keys(this.talkMap)) {
      if (!state.talks.some(talk => talk.title == title)) {
        this.talkMap[title].dom.remove();
        delete this.talkMap[title];
      }
    }
  }
}