javascript - 聚合物中的切换按钮问题

Question

我正在尝试使用按钮切换消息的显示。下面是我的代码。

class DisplayMessage extends PolymerElement {
  // DO YOUR CHANGES HERE
  static get template() {
    return html`
      <style>
        :host {
          display: block;
        }
      </style>

      <h2>Hello [[prop1]]!</h2>
      <button on-click="toggle">Toggle Message</button> <br />
      <template is="dom-if" if="{{user.authorise }}">
        <br />
        <span>I should now display message.</span>
      </template>
    `;
  }

  toggle() {
    // DO YOUR CHANGES HERE
    // hint: use set method to do the required changes
    
    //console.log(this.user);
    //this.user = !this.user
  }

  static get properties() {
    return {
      prop1: {
        type: String,
        value: 'user',
      },
      user: {
        type: Object,
        value: function () {
          return { authorise: false}; // HINT: USE BOOLEAN VALUES TO HIDE THE MESSAGE BY DEFAULT
        },
        notify: true,
      },
    };
  }
}

window.customElements.define('display-message', DisplayMessage);

我试着思考了几个小时，但无法解决。她的要求是单击按钮，单击处理程序切换应将用户属性中的授权值更改为 true。并再次单击为 false 等等。我需要在切换方法中使用 set 方法。我不知道如何做到这一点。请帮助我。

提前致谢。

Answer 1

为什么要为这么小的组件使用库/依赖项，可以使用本机代码完成

<display-message id=Message name=Cr5>You are authorized</display-message>
<script>
  customElements.define("display-message", class extends HTMLElement {
    static get observedAttributes() {
      return ["name", "authorized"]
    }
    connectedCallback() {
      this.innerHTML = `<h2>Hello <span>${this.getAttribute("name")}</span></h2><button>Toggle message</button><br><div style=display:none>${this.innerHTML}</div>`;
      this.querySelector('button').onclick = () => this._toggle();
    }
    _toggle(state) {
      let style = this.querySelector('div').style;
      style.display = state || style.display == "none" ? "inherit" : "none";
      this.toggleAttribute("authorized", state);
      console.log(Message.name, Message.authorized);
    }
    get name() { return this.getAttribute("name") }
    set name(value) {
      this.querySelector('span').innerHTML = value;
      this.setAttribute("name", value);
    }
    get authorized() { return this.hasAttribute("authorized")   }
    set authorized(value) { this._toggle(value) }
    
    attributeChangedCallback(name, oldValue, newValue) {
      if (oldValue) this[name] = newValue;
    }
  })
  Message.name = "Cr5";
  Message.authorized = true;
</script>