2

I was sitting on an issue trying to figure it out and then unexpectedly did something that worked! :)

But I have no idea why it is working??

Would appreciate it if someone could explain it to me.

What I wanted to do was: using Id values to determine whether the button should display or not, like :

If Id == 1 button should be shown.

and if Id >= 2 button should be hidden.

and I have another event where I toggle the Id's manually and the button Shows/Hides correctly as I change the values.

HTML

The thing that boggles me is ng-show="S == ph[0].PhaseId" because, in my explanation I said it should be determined with the Id's. and with this coding it does not (in my sense) show where it compares the value to the correct Id's. 

 <button ng-if="ph" type="button" class="col button button-small button-dark" ng-init="showMe(ph);" ng-show="S == ph[0].PhaseId">
Check In
</button>

Javascript

 $scope.showMe = function()
  {  
        $scope.S = true;
  }
  • If `ph[0].PhaseId` is `true`, then it'll show. What's so complicated in that? Also, you could as well do: `true === ph[0].PhaseId`. Use three `=`s. – cst1992 Apr 06 '16 at 12:19
  • It is because `ph[0].PhaseId` isn't the same value when it changes, it ranges from `1` too `7`. and only `1` should be true. there is no where in my coding where I say only `1` should be true? @cst1992 –  Apr 06 '16 at 12:22
  • Non-zero values will be treated as `true`. You should use `===`, it's stricter type checking, and will break the code. – cst1992 Apr 06 '16 at 12:23

4 Answers4

2

As a rule of thumb just test the exact code you put inside an ng-show (or ng-if or ng-hide) and verify that in a certain condition is evaluates to true. In this case with $scope.S = true the expression S == ph[0].PhaseIdevaluate to true. Why? Because == works a little different than in other languages, probably here you need ===.

For example true == 1; evaluates to true but true === 1; evaluates to false. Here a better reference.

Try to change == with ===

Community
  • 1
  • 1
Naigel
  • 9,086
  • 16
  • 65
  • 106
  • 1
    Indeed, `==` checks only for equality, whereas `===` checks for both equality and type, e.g. `boolean`. – cst1992 Apr 06 '16 at 12:26
0

I didn't get your question exactly but looking at the query, it seems that since you are calling showMe() initially, the value for your bool S will become true. Now for 1==true it will return true while for any other value that will return false. So it shows up when id is 1 and gets hidden for any other value.

Himanshu Mittal
  • 794
  • 6
  • 19
0

The thing is that you are using a non-strict comparison ('==') and types of the values are not being compared. true value is a 1 (basically), so true == 1 will return true, while true == 2 will return false. That's a pretty brief explanation, but that's how I see this :-)

Ivan Iankovskyi
  • 36
  • 4
-1

Simply use the following in ng-show. when the value is 1 it shows otherwise it hides.

ng-show="ph[0].PhaseId"
Gurpinder
  • 634
  • 1
  • 5
  • 18