I need to execute HttpClient get request synchronously so I found a solution on internet to use toPromise instead of subscribe and then await.
However I have noticed that the this.form = = this.formBuilder.group line of code executes before myAccount is initialized by the async call.
In other words I was expecting that the execution code will block until this.myAccount is initialized and then starts executing this.form = this.formBuilder.group line.
Am I understanding async/await in javascript correct. What do I need to do to achieve what I want - that is, wait with execution until this.myAccount is initialized by the call await this.accountService.getById(this.id).toPromise().
ngOnInit(): void {
this.getByIdSynchronously();
this.form = this.formBuilder.group({
scheduledDate: ['', Validators.required],
required: [''],
userAvailability: [''],
});
}
async getByIdSynchronously()
{
this.myAccount = await this.accountService.getById(this.id).toPromise();
}
I also have an html page with the first line of code looking like this:
<form [formGroup]="form" (ngSubmit)="onSubmit()" *ngIf="!isAdmin">
...
</form >
where isAdmin is a local function:
get isAdmin()
{
if(this.myAccount)
{
return this.myAccount.role == Role.Admin;
}
else{
return true;
}
}
which executes dozen of time before my async/await method finishes so I have to return some artificial true value until my this.myAccount is initialized.
Note
I have found solution to the first problem - just use then operator of the Promise. I can't find the solution for the second problem - to stop isAdmin being called from template html until this.myAccount is initialized. Is there a remedy for that?
Instead of Promises you should use Observables as Angular also encourages the use of Observables. The HTTPClient returns an observable so you can subscribe to it instead.
AccountService
getById(id: number): Observable<any> {
return this.httpClient.get(`URL goes here. ID goes into PARAMS`);
}
Then in your component subscribe to your API call. You can use another variable to stop isAdmin from being called continuously.
isLoaded: boolean = false;
ngOnInit(): void {
this.accountService.getById(this.id).subscribe(resp=>{
this.form = this.formBuilder.group({
scheduledDate: ['', Validators.required],
required: [''],
userAvailability: [''] });
this.isLoaded = true;
});
}
<form [formGroup]="form" (ngSubmit)="onSubmit()" *ngIf="isLoaded && !isAdmin">
...
</form>