javascript - 在angularjs中说早上晚上和下午

Question

我想创建一个返回 morning evening 和 afternoon 的指令。如果我用 java 脚本编写代码，这就是逻辑

var time = 00;


/* hour is before noon */
if ( time < 12 ) 
{
    document.write("Good Morning!");
}
else  /* Hour is from noon to 5pm (actually to 5:59 pm) */
if ( time >= 12 && time <= 17 )
{
    document.write("Good Afternoon!");
}
else  /* the hour is after 5pm, so it is between 6pm and midnight */
if ( time > 17 && time <= 24 )
{
    document.write("Good Evening!");
}
else  /* the hour is not between 0 and 24, so something is wrong */
{
    document.write("I'm not sure what time it is!");
}

如何使用指令在 Angular 中实现这一点

我的 Angular 应用dom是

<p> 12:00:01 </p>

我希望它呈现为 <p>afternoon </p>

Answer 1

我更喜欢过滤器而不是指令，它的实现非常简单，如下所示。

过滤器:

app.filter('greet', function() {
  return function(input) {
    if (input < 12) {
      return 'Good Morning';
    } else if (input >= 12 && input <= 17) {
      return 'Good Afternoon';
    } else if (input > 17 && input <= 24) {
      return 'Good Evening';
    } else {
      return "I'm not sure what time it is!";
    }
  };
});

HTML: <span>{{value | greet}}</span>

示例演示: http://plnkr.co/edit/5zs1zrxgeL7OT7ssT7Ak?p=preview