javascript - In Angular models, can you switch value type between JSON Object and String? -



javascript - In Angular models, can you switch value type between JSON Object and String? -

i have application @ work working on requires me display various fields based on value of associated rule.itemtype. issue coming across unable modify model info in ng-repeat if previous set value in rule.value string object displaying fields require object. when seek assign new values returns: typeerror: cannot assign read property 'course' of abc123.

i did find if value object display string of [object object], assuming comes object.prototype.tostring() function reading about, , if changed replace rule.value new string object. though direction works, if needing string object end @ above mentioned issue.

i have attached sample code demonstrate trying below plus data. forked, modified, , linked replier's plunker can see in action:

http://plnkr.co/edit/v4gsyc6mbyeggyjppvnc?p=preview

javascript:

var app = angular.module('plunker', []); app.controller('appctrl', function ($scope) { $scope.rules = [ {id: 1, itemtype: 'cs', value: {course: 'abc', number: '123'}}, {id: 2, itemtype: 'sa', value: 'abc123'} ]; });

html, angular v1.3.0:

<body> <div ng-controller="appctrl app"> <div ng-repeat="rule in rules"> rule {{$index+1}} <!-- alter itemtype rule --> <select ng-model="rule.itemtype"> <option value="sa">string</option> <option value="cs">object</option> </select> <!-- fields shown if rule.itemtype (sa: string, cs: object) --> <input type="text" ng-if="rule.itemtype === 'sa'" ng-model="rule.value" /> <span ng-if="rule.itemtype === 'cs'"> <input ng-model="rule.value.course" /> <input ng-model="rule.value.number" /> </span> </div> </div> </body>

update 1:

added suggestion ryan randall utilize ng-change='changetype(rule) provides appropriate behavior looking for, illustration plunker below.

http://plnkr.co/edit/bfahzj?p=preview

javascript changes:

// contributed by: http://stackoverflow.com/a/26702691/949704 $scope.typechange = function (rule) { if (rule.itemtype === 'cs') rule.value = {}; if (rule.itemtype === 'sa') rule.value = ''; };

html changes:

<!-- alter itemtype rule --> <select ng-model="rule.itemtype" ng-change="changetype(rule)"> <option value="sa">string</option> <option value="cs">object</option> </select>

one way avoid issue you're having explicitly set rule.value when rule.itemtype changes.

here's working plunker containing tweaks: http://plnkr.co/edit/rmfebe?p=preview

the next has been added select:

ng-change="typechange(rule)"

and next has been added controller:

$scope.typechange = function(rule) { if (rule.itemtype === 'cs') rule.value = {}; if (rule.itemtype === 'sa') rule.value = ''; };

javascript json angularjs type-conversion angular-ngmodel

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