Angular js - 值更改时突出显示 dom [英] Angular js - Highlight dom when value changes

问题描述

这里有角菜鸟.我想知道当范围中的值以某种方式发生变化时，更改 dom 的最佳方法是什么.我读到将 dom 操作逻辑放在控制器中并不好，这就是指令的工作.

Angular noobie here. I would like to know what is the best way to change the dom when a value in the scope changes by some means. I read that its not good to put the dom manipulation logic in the controller and thats the job of directives.

这里有一个 plunkr

Here is a plunkr

http://plnkr.co/edit/xWk5UBwifbCF2raVvw81?p=preview

基本上，当数据通过单击上面 plunkr 中的加载数据按钮更改时，我希望值更改的单元格自动突出显示.我不能让它为我的生活工作.

Basically when the data changes by clicking the load data button in the plunkr above, i want the cells whose values changed to highlight automatically. I cant get it to work for the life of me.

有什么帮助吗?

推荐答案

我认为最好观察每个 highlighter 的具体值，而不是观看整个集合.例如:

I think it would be better to observer a concrete value per highlighter instead of watching the whole collection. E.g.:

<td highlighter="person.firstName">{{ person.firstName }}</td>

这样，highlighter 指令可以非常简单，例如:

This way, the highlighter-directive could be very simple, like:

app.directive('highlighter', ['$timeout', function($timeout) {
  return {
    restrict: 'A',
    scope: {
      model: '=highlighter'
    },
    link: function(scope, element) {
      scope.$watch('model', function (nv, ov) {
        if (nv !== ov) {
          // apply class
          element.addClass('highlight');

          // auto remove after some delay
          $timeout(function () {
            element.removeClass('highlight');
          }, 1000);
        }
      });
    }
  };
}]);

尽管如此，要使此功能起作用，您必须告诉 angular 数据实际上已更改.目前情况并非如此，因为角度跟踪people 对象身份.覆盖它的那一刻，angular 将删除所有关联的 dom 元素.为此，请使用:

Though, for this to work you'll have to tell angular that the data actually changed. Currently this is not the case as angular tracks people by object-identity. The moment you overwrite it, angular will remove all associated dom-elements. To accomodate for this, use:

ng-repeat="person in people track by $index"

这将告诉 angular 将数组的索引视为身份.

which will tell angular to treat the index of the array as identity.

演示:http://jsbin.com/vutevifadi/1/

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