ngSwitchWhen doesn't work when duplicate whens are written - angular2-template

Question

I am learning angular2 using ng-book2 book and I was just playing around Built in directives.
I was reading about ngSwitch and I stumbled upon this feature where we can write multiple ngSwitchWhen with same conditions like following code:
<ul [ngSwitch]="choice">
<li *ngSwitchWhen="1">First choice</li>
<li *ngSwitchWhen="2">Second choice</li>
<li *ngSwitchWhen="3">Third choice</li>
<li *ngSwitchWhen="4">Fourth choice</li>
<li *ngSwitchWhen="2">Second choice, again</li>
<li *ngSwitchDefault>Default choice</li>
</ul>
which will output following result:
Second Choice
Second choice, again
I wrote code as below:
<div [ngSwitch]="myVar">
<div *ngSwitchWhen="myVar==1">My Var is 1</div>
<div *ngSwitchWhen="myVar==2">My Var is 2</div>
<div *ngSwitchWhen="myVar==3">My Var is 3</div>
<div *ngSwitchWhen="myVar==3">Special feature of ng Swtich</div>
<div *ngSwitchDefault>My Var is {{myVar}}</div>
</div>
which does not print output with same conditions.
I thought my code was proper but when I saw *ngSwitchWhen="myVar==3"
I found out my mistake.
But strangely it works properly except for repeated conditions
Is there any difference between these two conditions?
*ngSwitchWhen="2"
*ngSwitchWhen="myVar==3"
Which one to use?

Answer 1

ngSwitchWhen="2"
This expression checks the value of switchcase against the variable myVar(myVar=="6")
ngSwitchWhen="myVar==3"
Whereas this expression evaluates to myVar==(myVar==2) the value inside the parantheses return 1 if myVar is 2 and 0 if not