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HTML Settings

Here you can Sed posuere consectetur est at lobortis. Donec ullamcorper nulla non metus auctor fringilla. Maecenas sed diam eget risus varius blandit sit amet non magna. Donec id elit non mi porta gravida at eget metus. Praesent commodo cursus magna, vel scelerisque nisl consectetur et.

            
              <h2>
  The info below will change in <span id='timer'>5</span> seconds</h2>
<!-- 下面是 mvvm 中的 View层 -->
<!-- View层 start -->
<div id="school" class="school">
  <h3>XX Middle School</h3>
  <ul>
    <li>Class 18</li>
    <li>Grade 03</li>
  </ul>
</div>
<!-- View层 end -->
            
          
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              table {
  border: 1px solid #ddd;
  border-collapse: collapse;
}
td, th {
  border: 1px solid #ddd;
}
ul, li {
  list-style: none;
}
.school {
  margin-top: 10px;
  padding: 10px;
  border: 1px solid #ddd;
}
.school--yellow {
  border: 1px solid dark-yellow;
  color: #fff;
  background-color: yellow;
}
            
          
!
            
              // --- View层 请看Html代码段
// --------- Model层 ----------
var newPerson = {
  school: {
    name: "XX Middle School",
    classNumber: "18",
    grade: "03",
    vitualNode: {
      selector: "#school"
    }
  }
};

// --------- viewModel层 ----------
function updateSchool(newVal, oldVal) {
  var el = document.querySelector(newVal.vitualNode.selector || "#school");
  // 传统的拼接html字符串的方式实现更新视图View
  var compiled = _.template(
    "<h3>${ name }</h3><ul><li>Class ${ classNumber }</li><li>Grade ${ grade }</li></ul>"
  );
  el.innerHTML = compiled(newVal);
  if (newVal.vitualNode.data) {
    newVal.vitualNode.data.classNames &&
      (el.className = newVal.vitualNode.data.classNames);
    if (newVal.vitualNode.data.style) {
      Object.keys(newVal.vitualNode.data.style).forEach(function(key) {
        el.style[key] = newVal.vitualNode.data.style[key];
      });
    }
  }
}
Object.defineProperty(newPerson, "school", {
  set: function(x) {
    if (!_.isEqual(x, this.oldPropValue)) {
      // 数组或者对象的比较与普通的数值的比较不一样,要深度遍历进行比较
      console.log(x);
      updateSchool(x, this.oldPropValue);
      this.oldPropValue = x;
    } else {
      console.log("school的值没变");
    }
  },
  get: function() {
    console.log("in property get accessor");
    return this.oldPropValue;
  },
  enumerable: true,
  configurable: true
});

// --------- mvvm 数据驱动开发方式,现在只需修改newPerson的数据,View层的Dom节点会自动更新,如下:
setTimeout(function() {
  newPerson.school = {
    name: "YY Middle School",
    classNumber: "10",
    grade: "01",
    vitualNode: {
      selector: "#school",
      data: {
        classNames: "school school--yellow",
        style: {
          textShadow:
            "3px 3px 3px #720005, -3px -3px 3px #720005,3px 0 3px #720005,0 3px 3px #720005,0 -3px 3px #720005, -3px 0 3px #720005",
          borderRadius: "10px"
        }
      }
    }
  };
}, 5000);

// 下面只是计时器,与上面无关,set the timer
Object.prototype.delay = function(time, doSomething) {
  var self = this,
    startTime = time;
  if (self) {
    setTimeout(function() {
      doSomething(self, startTime);
    }, time);
  }
  return this;
};
var el = document.querySelector("#timer");
for (var i = 0; i <= 5; i++) {
  el.delay(i * 1000, function(self, startTime) {
    self.innerHTML = 5 - startTime / 1000;
  });
}

            
          
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