TS 2322 Type 'null' is not assignable to type 'string'

I have Angular 12 project which has typescript 4.2.3
I’m getting bunch of these errors. In this case, I’m passing appLang parameter to child component.

So here’s my html:

<app-bankcard-call-flows [appLang]="getLanguage()">

I’m trying to pull value from the coordinating component:

  public getLanguage() {
    this.appLang = this.language;
   }

I’m getting error:

TS2322: Type 'void' is not assignable to type 'string'.
<app-bankcard-call-flows [appLang]="getLanguage()"></app-bankcard-call-flows>

>Solution :

The method getLanguage() does not return anything so you’re essentially passing void to the [appLang] input while it expects a string.

Either use [appLang]="appLang" or change the method to return the appLang:

public getLanguage(): string {
    return this.language;
}