Using angularjs filter in input element

Question

Using angularjs filter in input element

I hope I haven't missed anything obvious in the doco, if I have I'm sure someone will help.

I'm using asp.net webapi to return a DTO, with date fields. These are serialized using JSON.Net (in format '2013-03-11T12:37:38.693').

I'd like to use a filter but in an INPUT element, is this possible or should I create a new filter or directive to accomplish this?

// this just displays the text value
<input ui-datetime type="text" data-ng-model="entity.date" /> 
// this doesn't work at all
<input ui-datetime type="text" data-ng-model="{{entity.date|date:'dd/MM/yyyy HH:mm:ss a'}}" /> 
// this works fine
{{entity.date|date:'dd/MM/yyyy HH:mm:ss a'}}

Is there any shortcut I'm missing?

angularjs
asp.net-web-api
angularjs-directive

Answer 1

In short: if you want your data to have a different representation in the view and in the model, you will need a directive, which you can think of as a two-way filter.

Your directive would look something like

angular.module('myApp').directive('myDirective', function() {
  return {
    require: 'ngModel',
    link: function(scope, element, attrs, ngModelController) {
      ngModelController.$parsers.push(function(data) {
        //convert data from view format to model format
        return data; //converted
      });

      ngModelController.$formatters.push(function(data) {
        //convert data from model format to view format
        return data; //converted
      });
    }
  }
});

HTML:

<input my-directive type="text" data-ng-model="entity.date" />

Here is a working jsFiddle example.

Answer 2

Having different values in your input field and in your model goes against the very nature of ng-model. So I suggest you take the simplest approach and apply your filter inside the controller, using a separate variable for formatted date, and employing watchers to keep formatted and original dates in sync:

HTML:

<input ui-datetime type="text" data-ng-model="formattedDate" />

JS:

app.controller('AppController', function($scope, $filter){

  $scope.$watch('entity.date', function(unformattedDate){
    $scope.formattedDate = $filter('date')(unformattedDate, 'dd/MM/yyyy HH:mm:ss a');
  });

  $scope.$watch('formattedDate', function(formattedDate){
    $scope.entity.date = $filter('date')(formattedDate, 'yyy/MM/dd');
  });

  $scope.entity = {date: '2012/12/28'};

});

Answer 3

Complete example that formats numbers, inserting spaces every 3 characters, starting from the end:

'use strict'
String::reverse = ->
  @split('').reverse().join('')

app = angular.module('app', [])
app.directive 'intersperse', ->
  require: 'ngModel'
  link: (scope, element, attrs, modelCtrl) ->
    modelCtrl.$formatters.push (input) ->
      return unless input?
      input = input.toString()
      input.reverse().replace(/(.{3})/g, '$1 ').reverse()
    modelCtrl.$parsers.push (input) ->
      return unless input?
      input.replace(/\s/g, '')

Usage:

<input ng-model="price" intersperse/>

Plunkr example: http://plnkr.co/edit/qo0h9z

Answer 4

You wouldn't need to create a new filter from zero, since angular has already a built-in filter for date types. http://docs.angularjs.org/api/ng.filter:date

I believe that's exactly what you need.