Fixed booleanAttrs to sync model.

[floydwch]

Current booleanAttrs can't sync model when asserted.

Using link instead of compile to fix this issue.

[floydwch]

Isn't this considered a bug?

<div ng-app="" ng-init="slave=false">
  Check me to check both: <input id="checkMaster" type="checkbox" ng-model="master"><br/>
  <input id="checkSlave" type="checkbox" ng-checked="master" ng-model="slave">
  {{slave}}
</div>

Check on #checkMaster should both change ng-model="master" and ng-model="slave".

But #checkSlave set ng-model="slave" only change its ng-model when manually check on #checkSlave.

[mhevery]

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[floydwch]

@mhevery I have signed it.

[mhevery]

Hi @floydsoft, sorry, I took a better look at this pull request, and we think what you are trying to do does not make sense. ng-checked creates a one-way data-binding but ng-model creates two-way databinding. In essence you have two models connected to the same input element, and i think that that is just wrong. I think ng-model and ng-checked should be used exclusively, ie one or the other but not together.

I am going to close this PR without merging it. Let me know if yo feel otherwise.

[floydwch]

@mhevery

So what's the right way to implement such requirement?

Why ng-checked just a one-way data-binding?

[mhevery]

I think it should all be done through ng-model

On Tue, Sep 4, 2012 at 6:44 PM, floydsoft notifications@github.com wrote:

@mhevery https://github.com/mhevery

So what's the right way to implement such requirement?

Why ng-checked just a one-way data-binding?

—
Reply to this email directly or view it on GitHubhttps://github.com//pull/1057#issuecomment-8285198.

[floydwch]

@mhevery consider following example, slave1 and slave2 cannot be group checked by master, we should use ng-checked, but ng-checked conflicts with ng-model, which store slave1 and slave2's states.

How to solve it?

<div ng-app="" ng-init="master=false;slave1=false;slave2=false">
  Check me to check both: <input id="checkMaster" type="checkbox" ng-model="master"><br/>
  <input id="checkSlave" type="checkbox" ng-model="slave1">
  {{slave1}}
  <input id="checkSlave2" type="checkbox" ng-model="slave2">
  {{slave2}}
</div>​

[floydwch]

@mhevery

I've clarified my thought, and post on forum, the original version I tweaked had problem that it must include ngModel, but that's just wrong.

How about

      require: '?ngModel',
      link: function(scope, element, attr, ngModel) {
        scope.$watch(attr[normalized], function ngBooleanAttrWatchAction(value) {
          attr.$set(attrName, !!value);
          if(ngModel) {
            ngModel.$setViewValue(!!value);
          }
        });
      }

Making ngChecked work with ngModel, and I think it doesn't mess up something.

[derokorian]

I think the problem here is that ngChecked is one way - it reads a value and affects the checked status of the input its on. ngModel is two way - it reads a value and affects the input but it also reads the input and affects the value.

Therefore, I feel (and clearly others do as well), that the problem is that ngChecked changes the checked status of a checkbox. The model on that checkbox is supposedly directly tied to the checked status of it, however we now see the checked status changing, without the model changing. I don't see how allowing this functionality would cause multiple two way bindings on an element, as the checkbox cannot affect the value(s) of the expression passed to it in ngChecked.