Checkbox should support null/undefined model

[sheppard30]

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Plunkr Case (Bug Reports)
http://plnkr.co/edit/PPIk2sjGNI9EyGhdkA9e?p=preview

Current behavior
I want to create a simple checkbox with my own event handler - just run method when checkbox is clicked but it generates error:

Checkbox.html:7 ERROR TypeError: Cannot read property 'concat' of undefined
at Checkbox.addValue (checkbox.ts:106)
at Checkbox.updateModel (checkbox.ts:76)
at Checkbox.onClick (checkbox.ts:66)
at Object.eval [as handleEvent] (Checkbox.html:7)
at handleEvent (view.ts:140)
at callWithDebugContext (services.ts:645)
at Object.debugHandleEvent [as handleEvent] (services.ts:241)
at dispatchEvent (util.ts:173)
at eval (element.ts:221)
at HTMLDivElement.eval (dom_renderer.ts:75)
at ZoneDelegate.invokeTask (zone.js@0.8.4?main=browser:398)
at Object.onInvokeTask (ng_zone.ts:253)
at ZoneDelegate.invokeTask (zone.js@0.8.4?main=browser:397)
at Zone.runTask (zone.js@0.8.4?main=browser:165)
at HTMLDivElement.ZoneTask.invoke (zone.js@0.8.4?main=browser:460)

Expected behavior
It should not fail.

Minimal reproduction of the problem with instructions
Click on checkbox and watch console log

Please tell us about your environment:
Windows 7

• Angular version: 2.0.X
  4.0.0

• PrimeNG version: 2.0.X
  4.0.1

• Browser:
  Chrome

[sudheerj]

This is because you didn't define model or value for default multi checkbox behavior
So either you should set binary=true or define model
#2870

[sheppard30]

@sudheerj with attribute "value" the issue persists. I do not need ngModel for this because I am going to use onChange(). ngModel should be optional in this case.

[sudheerj]

Yeah, it won't depend on value setting. The PR will give clear distinction between single and multi checkbox

[codedumper]

Will it solve the same issue in ReactiveForm ?
<p-checkbox formControlName="is_911_passthrough"></p-checkbox>
generate the same error (formControl is existing).

[cagataycivici]

I believe so.