Angular pipe to trim and contatenate strings with space between. Mostly for formatting names, which may include null/undefined values, or leading/trailing spaces

app.module.ts

// app.module.ts
import { MultiStringPipe } from './MultiString.pipe';

@NgModule({
  declarations: [
    //...
    MultiStringPipe,
  ],
})
export class AppModule {}

MutiString.pipe.ts

// MultiString.pipe.ts
import {
  Pipe,
  PipeTransform
} from '@angular/core';

@Pipe({ name: 'multiString' })
export class MultiStringPipe implements PipeTransform {
  function transform(...values: string[]): string {
    return values
      .reduce( (prev, curr) => 
        `${prev} ${(curr ?? '').trim()}`.trim(), 
        '');
  }
}

name-format.component.ts

// name-format.component.ts
import { Component } from '@angular/core';

@Component({
  selector: 'name-format',
  template: `
    <h2>Name Format</h2>
    <p>Name: {{ [firstName, middleName, lastName] | multiString }}</p>
  `
})

export class NameFormatComponent implements OnInit {
  @Input() firstName: string = 'George';
  @Input() middleName: string = 'P';
  @Input() lastName: string = 'Burdell';
  constructor() { }

  ngOnInit() { }

}