What is wrong with Angular's logical OR in option attribute? When [(ngModel)] is used in select the [selected] attribute doesn't affect the selection

I have an option in select like this:

<option [selected]=" impulse === 10 || isTraining " value="10">10</option>

When I have any possible value of impulse and isTraining is true my expectation is that the current option will be selected by default due to selected keyword in the dropdown, but it isn't. Are logical operators ever evaluated for the attributes required a boolean value?

The full select here is

<select class="form-control" name="flashFormatImpulse" id="field_flashFormatImpulses"
                            (change)="handleFlashImpulseSelection($event)" [(ngModel)]="impulseSelection" [disabled]="isStarted">
                        <option *ngIf="!isTraining" [selected]="impulse === 1" value="1">1</option>
                        <option *ngIf="!isTraining" [selected]="impulse === 2" value="2">2</option>
                        <option *ngIf="!isTraining" [selected]="impulse === 3" value="3">3</option>
                        <option *ngIf="!isTraining" [selected]="impulse === 4" value="4">4</option>
                        <option *ngIf="!isTraining" [selected]="impulse === 5" value="5">5</option>
                        <option *ngIf="!isTraining" [selected]="impulse === 6" value="6">6</option>
                        <option *ngIf="!isTraining" [selected]="impulse === 7" value="7">7</option>
                        <option *ngIf="!isTraining" [selected]="impulse === 8" value="8">8</option>
                        <option *ngIf="!isTraining" [selected]="impulse === 9" value="9">9</option>
                        <option [selected]="impulse === 10 || isTraining" value="10">10</option>
                    </select>

UPD

that is for code below:

<div class="form-group">
                    <label class="form-control-label" jhiTranslate="businesslogic.flashs.flashcard.impulse"
                           for="field_flashFormatImpulses">Flash Impulse</label>
                    <select class="form-control" name="flashFormatImpulse" id="field_flashFormatImpulses"
                            (change)="handleFlashImpulseSelection($event)" [(ngModel)]="impulseSelection" [disabled]="isStarted">
                        <option *ngIf="!isTraining" [selected]="impulse === 1" value="1">1</option>
                        <option *ngIf="!isTraining" [selected]="impulse === 2" value="2">2</option>
                        <option *ngIf="!isTraining" [selected]="impulse === 3" value="3">3</option>
                        <option *ngIf="!isTraining" [selected]="impulse === 4" value="4">4</option>
                        <option *ngIf="!isTraining" [selected]="impulse === 5" value="5">5</option>
                        <option *ngIf="!isTraining" [selected]="impulse === 6" value="6">6</option>
                        <option *ngIf="!isTraining" [selected]="impulse === 7" value="7">7</option>
                        <option *ngIf="!isTraining" [selected]="impulse === 8" value="8">8</option>
                        <option *ngIf="!isTraining" [selected]="impulse === 9" value="9">9</option>
                        <option [selected]="impulse === 10 || isTraining" value="10">10</option>
                    </select>
                </div>
                <div>
                    <select class="form-control">
                        <option [selected]="true" value="10">10</option>
                    </select>
                </div>

and the effect is still the same when we change the code to

<div class="form-group">
                    <label class="form-control-label" jhiTranslate="businesslogic.flashs.flashcard.impulse"
                           for="field_flashFormatImpulses">Flash Impulse</label>
                    <select class="form-control" name="flashFormatImpulse" id="field_flashFormatImpulses"
                            (change)="handleFlashImpulseSelection($event)" [(ngModel)]="impulseSelection" [disabled]="isStarted">
                        <option *ngIf="!isTraining" [selected]="impulse === 1" value="1">1</option>
                        <option *ngIf="!isTraining" [selected]="impulse === 2" value="2">2</option>
                        <option *ngIf="!isTraining" [selected]="impulse === 3" value="3">3</option>
                        <option *ngIf="!isTraining" [selected]="impulse === 4" value="4">4</option>
                        <option *ngIf="!isTraining" [selected]="impulse === 5" value="5">5</option>
                        <option *ngIf="!isTraining" [selected]="impulse === 6" value="6">6</option>
                        <option *ngIf="!isTraining" [selected]="impulse === 7" value="7">7</option>
                        <option *ngIf="!isTraining" [selected]="impulse === 8" value="8">8</option>
                        <option *ngIf="!isTraining" [selected]="impulse === 9" value="9">9</option>
                        <option [selected]="true" value="10">10</option>
                    </select>
                </div>
                <div>
                    <select class="form-control">
                        <option [selected]="true" value="10">10</option>
                    </select>
                </div>

i.e. having the same [selected] for both (but a different look).

I.e. <option [selected]="true" value="10">10</option> works and <option [selected]="impulse === 10 || isTraining" value="10">10</option> is not

UPD 2

That's how it looks for code below:

<div class="form-group">
                    <label class="form-control-label" jhiTranslate="businesslogic.flashs.flashcard.impulse"
                           for="field_flashFormatImpulses">Flash Impulse</label>
                    <select class="form-control" name="flashFormatImpulse" [(ngModel)]="impulseSelection" id="field_flashFormatImpulses"
                            (change)="handleFlashImpulseSelection($event)"  [disabled]="isStarted">
                        <option *ngIf="!isTraining" [selected]="impulse === 1" value="1">1</option>
                        <option *ngIf="!isTraining" [selected]="impulse === 2" value="2">2</option>
                        <option *ngIf="!isTraining" [selected]="impulse === 3" value="3">3</option>
                        <option *ngIf="!isTraining" [selected]="impulse === 4" value="4">4</option>
                        <option *ngIf="!isTraining" [selected]="impulse === 5" value="5">5</option>
                        <option *ngIf="!isTraining" [selected]="impulse === 6" value="6">6</option>
                        <option *ngIf="!isTraining" [selected]="impulse === 7" value="7">7</option>
                        <option *ngIf="!isTraining" [selected]="impulse === 8" value="8">8</option>
                        <option *ngIf="!isTraining" [selected]="impulse === 9" value="9">9</option>
                        <option [selected]="impulse === 10 || isTraining" value="10">10</option>
                    </select>
                </div>
                <div class="form-group">
                    <select class="form-control" >
                        <option *ngIf="!isTraining" [selected]="impulse === 3" value="3">9</option>
                        <option *ngIf="!isTraining" [selected]="impulse === 9" value="9">9</option>
                        <option [selected]="impulse === 10 || isTraining" value="10">10</option>
                    </select>
                </div>

                <div>impulse {{impulse}}, isTraining {{isTraining}}, result: {{impulse === 10 || isTraining}}</div>

                <select class="form-control">
                    <option [selected]="impulse === 10 || isTraining" value="10">10</option>
                </select>

The problem with selection correlates with using the [(ngModel)]="impulseSelection" for the selector (that is a binding for value, used on the controller side) and is initialized as

impulseSelection = 3;

So the associated binding is always overriding the value of the selector to 3 while it is not present there. It looks like the only solution is to force this impulseSelection value to 10 when isTraining is assigned to true.

there's no reason why that should not be working. Check your logs for javascript errors. If none start with and empty select statement and build it back to what you have, one piece at a time until you find the problem.

I also like to add the values to the html just to be sure they are what you think they are. like this:

<div>impulse {{impulse}}, isTraining {{isTraining}}, result: {{impulse === 10 || isTraining}}</div>

<select class="form-control">
  <option [selected]="impulse === 10 || isTraining" value="10">10</option>
</select>