Invalid Character Error Angular

I am getting ERROR DOMException [InvalidCharacterError: "String contains an invalid character" code: 5 nsresult: 0x80530005 location: http://localhost:4200/vendor.bundle.js:67608] when trying to compile an Angular component with a custom attribute directive. My code for the AppComponent, Directive and base template is given below:

leftAlign.directive.ts

import {
  Directive,
  HostListener,
  HostBinding,
  Input,
  Output,
  ElementRef,
  Renderer2 // for host class binding
 } from '@angular/core';

@Directive({
  selector: '[leftAlign]'
})
export class LeftAlignDirective {

  public constructor(
    private el: ElementRef,
    private renderer: Renderer2
  ) {
    this.renderer.addClass(this.el.nativeElement, 'ui leftAlign');
  }
}

app.component.ts

import { Component } from '@angular/core';
import { LeftAlignDirective } from './Directives/left-align.directive';


@Component({
  selector: `app-root`,
  templateUrl: './app.component.html'
})
export class AppComponent {
  public static SemanticUiBaseDir = '../../semantic/dist/';
  public getSemanticeUiBaseDir() : string{
    return AppComponent.SemanticUiBaseDir;
  }
  public constructor() {}
}

app.component.html

!--
  @ semantic-ui.min.css
-->
<link rel="stylesheet" type="text/css" href="/home/zerocool/km-live/FrontEndComponent/semantic/dist/semantic.css">

<!--
  @ @semantic.min.js
-->
<script src="./home/zerocool/km-live/FrontEndComponent/semantic/semantic.js"></script>

<p leftAlign>This should be aligned left!</p>

I am interested in understanding the following: 1. What causes such errors? 2. What caused the error in this case?

Thanks

The problem is the space in addClass, it's not allowed.

I get a much more descriptive error when I try to do this

ERROR DOMException: Failed to execute 'add' on 'DOMTokenList': The token provided ('ui leftAlign') contains HTML space characters, which are not valid in tokens.

You'll need to add the two classes individually.

this.renderer.addClass(this.el.nativeElement, 'ui');
this.renderer.addClass(this.el.nativeElement, 'leftAlign');

On a side note you should refer to AppComponent as this from inside itself.

export class AppComponent {
  public static SemanticUiBaseDir = '../../semantic/dist/';
  public getSemanticeUiBaseDir() : string{
    return this.SemanticUiBaseDir; // I changed AppComponent to this here
  }
  public constructor() {}
}