Angular 2 ngSwitchCase, OR operator not working

PaladiN picture PaladiN · May 4, 2017 · Viewed 41.1k times · Source

I have multiple switch statement but for some case i need the common case. So, i am trying the

OR operator => ||

Example:

        <ng-container [ngSwitch]="options">
            <ng-container *ngSwitchCase="'a'">Code A</ng-container>
            <ng-container *ngSwitchCase="'b'">Code B</ng-container>
            <ng-container *ngSwitchCase="'c'">Code C</ng-container>
            <ng-container *ngSwitchCase="'d' || 'e' || 'f'">Common Code</ng-container>
            <ng-container *ngSwitchDefault>Code Default</ng-container>
        </ng-container>

Output:

if case = 'd' returns Common Code
else if case = 'e' and 'f' returns the Code Default 

Here the second last case consists of multiple cases, and now by default the case 'd' is only working and not working for case 'e' and 'f'.

I can't see any multiple case inside the ngSwitchCase docs:

https://angular.io/docs/ts/latest/api/common/index/NgSwitchCase-directive.html https://angular.io/docs/ts/latest/api/common/index/NgSwitch-directive.html

Doesn't Angular 2 supports the || operator in the ngSwitchCase?

Answer

G&#252;nter Z&#246;chbauer picture Günter Zöchbauer · May 4, 2017

If you evaluate 'd' || 'e' || 'f' the result is 'd' and when options is not 'd', then it doesn't match. You can't use ngSwitchCase that way.

This would work:

    <ng-container [ngSwitch]="true">
        <ng-container *ngSwitchCase="options === 'a'">Code A</ng-container>
        <ng-container *ngSwitchCase="options === 'b'">Code B</ng-container>
        <ng-container *ngSwitchCase="options === 'c'">Code C</ng-container>
        <ng-container *ngSwitchCase="options === 'd' || options === 'e' || options === 'f'">Common Code</ng-container>
        <ng-container *ngSwitchDefault>Code Default</ng-container>
    </ng-container>