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HTML

              
                <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 -->
              
            
!

CSS

              
                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;
}
              
            
!

JS

              
                // --- 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;
  });
}

              
            
!
999px

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