How do I set the value property in AngularJS' ng-options?

javascript

angularjs

ng-options

dropdown

byAnton Shumikhin·Sep 26, 2024

To bind a specific property to the model in AngularJS ng-options, you need to form an association between the property you want as the value and the as keyword, followed by the label expression. Use the syntax valueProperty as displayText for item in array to achieve this. Here's the gist:

<select ng-model="model.property" ng-options="item.valueProperty as item.displayText for item in array">
</select>

In this code, item.valueProperty becomes the actual value bound to model.property when an item is selected, and not merely a display value.

Still have doubts? Here's a nuts and bolts version:

<select ng-model="user.favoriteColor" ng-options="color.id as color.shade for color in rainbow">
</select>

Here, Angular gets nostalgic and says something romantic like: "Whenever user selects a shade of color, I'll remember its id as their favorite!" 🌈

Displaying Complex Data Structures

If you're dealing with complex data structures, ng-options is ready to roll out the red carpet for track by:

<select ng-model="world.tallestMountain" ng-options="mountain.name for mountain in mountainRange track by mountain.elevation">
</select>

This is Angular's way of saying: "I'll keep a track of mountains by their elevation; and just like high school yearbook, no duplicates allowed!" ⛰️

Initial Option Savvy

The prefered way to greet users with a default option:

<select ng-model="user.originPlanet">
  <option value="">Check your birth certificate</option>
</select>

However, If ng-options is at the wheel, AngularJS takes the passenger seat and adds an empty option whenever the model is null or undefined. To skip that route, set your model to a valid option:

$scope.user.originPlanet = $scope.planets[0].name;

Angular says, "Alright, everyone's from Earth until proven Martian!"🚀

Understanding Data Sources

Some golden tickets to remember:

For array data sources, remember: ng-options is a fan of indices, uses them as values.
For objects, it gets attracted to property names as values.

Evading common pitfalls

Consider these to avoid reaching for a hammer:

Empty starting point: Use ng-model to start effectively.
Nested objects: Learn the art of track by to manage complex objects.
Submitting forms: Toss in a hidden input which binds to the selected option value when submitting a form is on your list.

Mastering practical examples

Imagine you are assigning a dropdown from a JSON array:

$scope.fruits = [
  { id: 'apple', label: 'Red Apple' },
  { id: 'banana', label: 'Yellow Banana' },
  { id: 'grape', label: 'Purple Grapes' }
];

Setting up the dropdown with ng-options to bind the id as the value:

<select ng-model="basket.selectedFruit" ng-options="fruit.id as fruit.label for fruit in fruits">
</select>

Here, "Who ate my Red Apple?" will make Angular confess basket.selectedFruit was 'apple'.🍎

Structuring for better User Experience

A good dropdown:

Speaks to the user intuitively.
Uses meaningful labels and corresponding values.
Follows a logical sequence that aligns with user necessity.

Remember folks, user experience is the key to digital sustainability!

explain-codes / Javascript / How do I set the value property in AngularJS' ng-options?

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Displaying Complex Data Structures Initial Option Savvy Understanding Data Sources Evading common pitfalls Mastering practical examples Structuring for better User Experience