javascript 当输入字段为空时，AngularJS 过滤器比较器在显示 ng-repeat 列表时为真
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AngularJS filter comparator true while displaying ng-repeat list when input field is empty
提问by ZvKa
I'm going off by this example fiddle where it demonstrates the use of comparator parameter to filter exact matches....:
我将通过这个示例小提琴开始，它演示了使用比较器参数来过滤精确匹配....：
http://jsfiddle.net/api/post/library/pure/
http://jsfiddle.net/api/post/library/pure/
priority is a number from 1-100, but I have it input as text and filtered as string so any data that includes a substring will also pass through the ng-repeat...like when I type 1 it will also display 11, 111, 132 etc...which is how I came across the :true comparator.
优先级是 1-100 之间的一个数字，但我将它作为文本输入并作为字符串过滤，因此任何包含子字符串的数据也将通过 ng-repeat...就像当我输入 1 时，它也会显示 11, 111 , 132 等等...这就是我遇到 :true 比较器的方式。
I've read other stackflow answers suggesting to write custom filter functions but with the true comparator it looks like I can achieve what I want just by:
我已经阅读了其他建议编写自定义过滤器函数的堆栈流答案，但使用真正的比较器看起来我可以通过以下方式实现我想要的：
<input type="text" class="form-control" id="search.priority"
title='Priority number to filter by'
ng-model="search.priority" >
<tr ng-repeat="workflowItem in workflows | filter:search:true">
<td>{{workflowItem.priority}}</td>
where it does only filter the exact matches. However, obviously it does not pass anything when the input field is empty since nothing matches the empty string.
它只过滤精确匹配的地方。但是，显然当输入字段为空时它不会传递任何内容，因为没有任何内容与空字符串匹配。
My question is: Is there a way I can allow ng-repeat to still display everything when the field is empty while keeping the exact match filter? Appreciate everyone's time!
我的问题是：有没有一种方法可以让 ng-repeat 在字段为空时仍然显示所有内容，同时保持精确匹配过滤器？珍惜大家的时间！
回答by Joel Skrepnek
You'll want to use a custom comparator function. It will allow you to perform a strict comparison except when the predicate is falsy.
您将需要使用自定义比较器函数。它将允许您执行严格的比较，除非谓词为假。
Your markup would then be:
您的标记将是：
<input type="text" class="form-control" id="search.priority"
title='Priority number to filter by'
ng-model="search.priority" >
<tr ng-repeat="workflowItem in workflows | filter:search:exceptEmptyComparator">
<td>{{workflowItem.priority}}</td>
And define the comparator function on your controller:
并在您的控制器上定义比较器功能：
$scope.exceptEmptyComparator = function (actual, expected) {
if (!expected) {
return true;
}
return angular.equals(expected, actual);
}
That should do the trick.
这应该够了吧。
