ng-value and select elements

[justinwinslow]

According to the documentation (https://docs.angularjs.org/api/ng/directive/ngValue), ng-value should work with select elements but that's not the case. If you change the plunker in the example to be a select box "unicorn" does not end up selected.

[Narretz]

input[select] doesn't even make sense, there's no such thing. Unless I'm missing something, this should simply be removed.

[justinwinslow]

Hmm - I guess last night I was thinking ng-value on options populated by ng-repeat would look cleaner than the selected directive. I had also seen mention elsewhere that ng-value could coerce null to select an empty value. Not sure if that makes sense.

[jeffbcross]

Technically ngValue works on hard-coded options within a select, such as:

<select>
  <option ng-value="names[0]">{{names[0]}}</option>
  //value = pizza
</select>

A PR to the docs would be good to clarify this.

[kennardconsulting]

+1

This doesn't seem to work as advertised for booleans. See this Plunker: http://plnkr.co/1Nf5xCNBYBvEyRHMvHhI

I cannot get the OPTIONS to deal in booleans. It keeps switching the type to a string?

[kennardconsulting]

Hi Narretz,

Can you please clarify how this relates to 'doesn't work with booleans' (see my Plunker above). Or is there now a separate issue for that?

Regards,

Richard.

[Narretz]

@kennardconsulting
Richard, I closed this issue because it was referenced in a PR. Initially, it was about docs, so I didn't take your issue into consideration. Can you please open another issue about this?

[kennardconsulting]

@Narretz yes, I would be happy to. Before I do, however, could you please clarify my question (as it is related to the documentation you just modified). The question is: when you use ng-value on an option, is it expected that the expression always gets converted to a string? So...

$scope.myBooleanScopeValue = true;
...
<option ng-value="myBooleanScopeValue">

...will always return "true" never true? This causes problems, as can be seen in the Plunker.

[Narretz]

@kennardconsulting
It is indeed expected that ng-value can only deal with string values. That is because it $watches the expression inside ng-value and sets the result to the value of option, which is then picked up by the select directive to populate the model. And since html attributes can only contain strings, ng-value can only be used for strings.

[Narretz]

Note that the documation for select has recently been updated with this info: https://code.angularjs.org/snapshot/docs/api/ng/directive/select

[Narretz]

Correction: only using option together with ng-value does not support values other than strings. Angular actually supports this for input[radio] via the attributes getters / setters.

[kennardconsulting]

@Narretz thanks for investigating this for me. I think you have identified the source of confusion: some parts of Angular support values other than strings, others not.

'Pure' html does not support boolean radio buttons, but Angular does (as you said). Is there not an approach that will allow a select box of booleans?

[Narretz]

You can use ngOptions: https://docs.angularjs.org/api/ng/directive/select

[kennardconsulting]

Much appreciated. Thanks.