Explain the principle of Vue monitoring data change in detail

2021-08-03 08:25:55
OfStack

I recently in the study of Vue, from the Internet query a lot about Vue monitoring data change principle, a little streamlined to do under the sharing.

Shallow monitoring


<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title> Shallow monitoring </title>
  <meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=0">
  <meta name="apple-mobile-web-app-capable" content="yes">
  <meta name="apple-mobile-web-app-status-bar-style" content="black">
  <script src="../js/vue1.0.js"></script>
  <script src="../js/vue-resource.js"></script>
  <script>
    window.onload = function(){
      var vm = new Vue({
        el:'#box',
        data:{
          a:111,
          b:2
        }
      });
      vm.$watch('a',function(){
        alert(' It has changed ');
      });
      document.onclick = function(){
        vm.a = 1;
      }
    }
  </script>
</head>
<body>
<div id="box">
  {{a}}
  <hr>
  {{b}}
</div>
</body>
</html>

Depth monitoring


<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title> Depth monitoring </title>
  <meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=0">
  <meta name="apple-mobile-web-app-capable" content="yes">
  <meta name="apple-mobile-web-app-status-bar-style" content="black">
  <script src="../js/vue1.0.js"></script>
  <script src="../js/vue-resource.js"></script>
  <script>
    window.onload = function(){
      var vm = new Vue({
        el:'#box',
        data:{
          json:{name:'abcdef',age:'16'},
          b:2
        }
      });
      vm.$watch('json',function(){
        alert(' It has changed ');
      },{deep:true});
      document.onclick = function(){
        vm.json.name = "aaaaaa";
      }
    }
  </script>
</head>
<body>
<div id="box">
  {{json | json}}
  <hr>
  {{b}}
</div>
</body>
</html>