$urlMatcherFactoryProvider.type - decoded `null` parameter values are interpreted as `undefined`

[tmcgann]

I created a type of nullable int parameter type (int?) where all non-integer values are treates as null. However, when parameter values are decoded and null is returned for non-integer values, transition.params() and $transition$.params() show parameters as undefined when I would expect them to be null.

Is there a bug with the way null parameter values are being interpreted when decoded? Why do I keep seeing undefined instead of null even when null is returned by the decoder?

Plunker: http://plnkr.co/edit/hk6vkZOIJ1R1glxXdXLm?p=preview

[christopherthielen]

This is related to array mode handling in the parameter type. Query parameters are automatically in array mode = "auto". Array mode creates two "replacements". Both the empty string "" and null are mapped to undefined.

To address this, either turn array mode off or supply your own replace property (an empty array should do).

    params: {
      x: {
        type: 'int?', 
        array: false,
        /* replace: [] // either or */
      }
    },

http://plnkr.co/edit/T7YCgKGfmmpkpY4W5cZs?p=preview

[christopherthielen]

This plunker highlights an additional issue. It appears that during URL synchronization, compares parameters using == instead of using the typed parameter's equals function.

This problem can be seen when clicking the null link right after the plunk loads. No transition occurs. However, clicking he 1 or 2 link first, and then the null link, a transition occurs.

[tmcgann]

Sincerely sorry to waste your time over a misunderstanding with parameters. Thanks for the guidance though!

While setting array: false worked great for me in the plunker, in my actual app, I found that it wasn't enough. I thought it might be because I was performing a transition redirect in an onBefore hook, but when I tried to emulate it in the simple plunker example I couldn't get the same behavior I'm seeing in my app: http://plnkr.co/edit/y5QewL6btvbirADBif1Q?p=preview.

Per your alternate recommendation I ended up using replace because I could see when I stepped through the code that null kept getting replaced with '' by the array mode default replace settings. My replaced ended up looking something like this:

replace: [ { from: null, to: null} ]

Your empty array suggestion didn't seem to work for me. I also didn't see it working in the plunker you provided, in that x: null didn't show up in the parameters even though the query string updated appropriately. But maybe I was misinterpreting what you said.

Just thought I'd share in case others came across the same problem.

Thanks again for your help...and the quick response!

[stale]

This issue has been automatically marked as stale because it has not had
recent activity. It will be closed if no further activity occurs.

This does not mean that the issue is invalid. Valid issues
may be reopened.

Thank you for your contributions.