State dropdown in Angular dynamically updates based on the country selected

Question

State dropdown in Angular dynamically updates based on the country selected

I am in search of a contextual state dropdown menu that is linked to the country, ensuring only relevant states are displayed.

I have explored these two solutions for guidance in my project.

Angularjs trigger country state dependency

angularjs dependant dropdown option value

However, I am facing difficulties in getting them to function and believe there may be something I am overlooking.

My ideal scenario would involve utilizing an existing ng filter, although it appears that this method is solely effective on arrays and not objects.

 <select ng-model="user.state" ng-options="state.name for state in states track by state.id | filter:state.countryid = user.country.id">

I attempted converting the object into an array, but that approach did not yield successful results.

While I could develop a custom filter, I would prefer to avoid that route if possible.

 <select ng-model="user.state" ng-options="state.name for state in states track by state.id | customStateFilter:user.country.id">

It seems like there must be a way to make ng-options work without altering the data directly.

Is there an Angular filter available that can manipulate objects, or is there a method to dynamically apply conditional logic to filter out objects?

javascript angularjs

Answer 1

Answer №1

Your code has a few issues that need to be addressed. Firstly, the placement of track by should come after the filter in your array. Secondly, the built-in filter filter only works on arrays and not objects. For objects, a custom filter is required. Lastly, the syntax you used for the expression in the filter function is incorrect. The correct way to provide an expression is either as a string, an object specifying which property to match against, or a predicate function. In this case, an object is needed. To fix these issues, your code should look like this:

<select ng-model="selectedState"
        ng-options="state.name for state in states | filter: {countryid: user.country.id}:true track by state.id">
  <option value="">select statelt;/option>
</select>

Answer 2

Your code has a few issues that need to be addressed. Firstly, the placement of track by should come after the filter in your array. Secondly, the built-in filter filter only works on arrays and not objects. For objects, a custom filter is required. Lastly, the syntax you used for the expression in the filter function is incorrect. The correct way to provide an expression is either as a string, an object specifying which property to match against, or a predicate function. In this case, an object is needed. To fix these issues, your code should look like this:

<select ng-model="selectedState"
        ng-options="state.name for state in states | filter: {countryid: user.country.id}:true track by state.id">
  <option value="">select statelt;/option>
</select>

State dropdown in Angular dynamically updates based on the country selected

Answer №1

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