AngularJs: How to set radio button checked based on model

Ended up just using the built-in angular attribute ng-checked="model"

If you have a group of radio button and you want to set radio button checked based on model, then radio button which has same value and ng-model, is checked automatically.

<input type="radio" value="1" ng-model="myRating" name="rating" class="radio">
<input type="radio" value="2" ng-model="myRating" name="rating" class="radio">
<input type="radio" value="3" ng-model="myRating" name="rating" class="radio">
<input type="radio" value="4" ng-model="myRating" name="rating" class="radio">

If the value of myRating is "2" then second radio button is selected.

One way that I see more powerful and avoid having a isDefault in all the models is by using the ng-attributes ng-model, ng-value and ng-checked.

ng-model: binds the value to your model.

ng-value: the value to pass to the ng-model binding.

ng-checked: value or expression that is evaluated. Useful for radio-button and check-boxes.

Example of use: In the following example, I have my model and a list of languages that my site supports. To display the different languages supported and updating the model with the selecting language we can do it in this way.

<!-- Radio -->
<div ng-repeat="language in languages">

  <div>
    <label>

      <input ng-model="site.lang"
             ng-value="language"
             ng-checked="(site.lang == language)"
             name="localizationOptions"
             type="radio">

      <span> {{language}} </span>

    </label>
  </div>

</div>
<!-- end of Radio -->

Our model site.lang will get a language value whenever the expression under evaluation (site.lang == language) is true. This will allow you to sync it with server easily since your model already has the change.

Use ng-value instead of value.

ng-value="true"

Version with ng-checked is worse because of the code duplication.