如何筛选具有多个条件的数据

Question

I have some alarm data in my list and i want to filter them based on some condition like if there are more than one alarm of type pull_Alarm and emergency_alarm in same location then give priority to emergency alarm.

Here is my list:
[
    {
        alarmType:"Normal_ALARM"
        location:"Ward5"
        severity:"URGENT"
    },
    {
        alarmType:"Emergency_Alarm
        location:"Ward1"
        severity:"URGENT"
    },
    {
        alarmType:"PULL_Alarm"
        location:"Ward1"
        severity:"NORMAL"
    }
]

What i want a list after filter should be only

[
  {
    alarmType:"Normal_ALARM"
    location:"Ward5"
    severity:"URGENT"
  },
  {
    alarmType:"Emergency_Alarm
    location:"Ward1"
    severity:"URGENT"
  }
]

Can someone suggest me how i can apply filter on these condition.

Answer 1

Create one filter with switch cases or add if else conditions.

.filter("alarmFilter", function () {
    // write condition what ever you want to add
});

And apply this filter to your expression where you want to apply condition.

Answer 2

Write filter

$scope.filter1 = function(item)
    {
        return (item.severity == 'URGENT');
    };

and then use it

<div ng-repeat="item in object| filter:filter1">{{item.alarmType}}</div>

JSFIDDLE http://jsfiddle.net/Lvc0u55v/8866/

Answer 3

You can create a custom filter, as below.

angular.module('myFilters', []).
filter('byAlarmCount', function() {
  return function(alarms, severity) {
    var items = {
      severity: severity,
      out = []
    };
    angular.forEach(alarms, function(v, k)) {
        if (this.severity[v.severity] === true) {
          this.out.push(v);
        }
      }
    return items.out;
  }
});

DOM as below

<ul>
    <li ng-repeat="alarm in list | byAlarmCount:severityFilter">{{alarm.location}: {{alarm.alarmType}}</li>
</ul>

Answer 4

If you are looking to do some complex filtering then its better to look at some third party JS libraries like lodash ( https://lodash.com/ ) or Underscore ( http://underscorejs.org/ ).

These provide a wide range of utilities that can be used for filtering, mapping and other common utility functions.

For example for this current scenario you can use _.where / _.filter from underscorejs.

var filteredAlarms = _.where(<YOUR LIST>, { severity: NORMAL, alarmType: ...});