AngularJS : Custom filters and ng-repeat

Question

I'm an AngularJS newbie and I'm building up a small proof-of-concept car hire listings app that pulls in some JSON and renders out various bits of that data via an ng-repeat, with a couple of filters:

   <article data-ng-repeat="result in results | filter:search" class="result">
        <header><h3>{{result.carType.name}}, {{result.carDetails.doors}} door, &pound;{{result.price.value}} - {{ result.company.name }}</h3></header>
            <ul class="result-features">
                <li>{{result.carDetails.hireDuration}} day hire</li>
                <li data-ng-show="result.carDetails.airCon">Air conditioning</li>
                <li data-ng-show="result.carDetails.unlimitedMileage">Unlimited Mileage</li>
                <li data-ng-show="result.carDetails.theftProtection">Theft Protection</li>
            </ul>
    </article>

    <h2>Filters</h2>

    <h4>Doors:</h4> 
    <select data-ng-model="search.carDetails">
        <option value="">All</option>
        <option value="2">2</option>
        <option value="4">4</option>
        <option value="9">9</option>
    </select>

    <h4>Provider:</h4>
    Atlas Choice <input type="checkbox"  data-ng-model="search.company" ng-true-value="Atlas Choice" ng-false-value="" value="Atlas Choice" /><br>
    Holiday Autos <input type="checkbox"  data-ng-model="search.company" ng-true-value="Holiday Autos" ng-false-value="" value="Holiday Autos" /><br>
    Avis <input type="checkbox"  data-ng-model="search.company" ng-true-value="Avis" ng-false-value="" value="Avis" /><br>      

Now I want to create a custom filter in my controller, that can iterate over the items in my ng-repeat and return only the items that meet certain criteria - for example, I might create an array of values based on which 'provider' checkboxes are checked, then evaluate each ng-repeat item against that. I just can't work out how I'd do that though, in terms of the syntax - can anyone help?

Here's my Plunker: http://plnkr.co/edit/lNJNYagMC2rszbSOF95k?p=preview

Answer 1

If you want to run some custom filter logic you can create a function which takes the array element as an argument and returns true or false based on whether it should be in the search results. Then pass it to the filter instruction just like you do with the search object, for example:

JS:

$scope.filterFn = function(car)
{
    // Do some tests

    if(car.carDetails.doors > 2)
    {
        return true; // this will be listed in the results
    }

    return false; // otherwise it won't be within the results
};

HTML:

...
<article data-ng-repeat="result in results | filter:search | filter:filterFn" class="result">
...

As you can see you can chain many filters together, so adding your custom filter function doesn't force you to remove the previous filter using the search object (they will work together seamlessly).