Implementation of logger based on adapter pattern in the Typescript

gistfile1.js

/** A unified logging interface */
interface Logger{
  log(msg: string): void;
}
/** Factory for enums */
class LOGGER_TYPE{
  static CONSOLE:string="CONSOLE";
  static ALERT:string="ALERT";
  static DISPLAY:string="DISPLAY";
}
class LogAdapterFactory{
  static createLogger(type:string): Logger{
    switch(type){
    case LOGGER_TYPE.CONSOLE:
      return new ConsoleLogger();
    case LOGGER_TYPE.ALERT:
      return new AlertLogger();
    case LOGGER_TYPE.DISPLAY:
      return new DisplayLogger();
    }
    return null;
  }
}
class ConsoleLogger implements Logger{
  log(msg:string){
    console.log(msg);
  }
}
class AlertLogger implements Logger{
  log(msg:string){
    alert(msg);    
  }
}
class DisplayLogger implements Logger{
  display:HTMLDivElement;
  count:number;
  constructor(){
    this.count = 0;
    this.display = <HTMLDivElement>document.createElement("div");
    this.display.style.position="absolute";
    this.display.style.top="0px";
    this.display.style.right="0px";
    this.display.style.width="200px";
    this.display.style.background="#ddffdd";
    this.display.style.padding="10px";
    this.display.style.fontSize="10px";
    document.body.appendChild(this.display);
  }
  log(msg:string){
    if(this.count > 10){
      this.display.removeChild(this.display.childNodes[0]);
    }
    else{
      this.count++;
    }
    this.display.innerHTML += "<div>"+msg+"</div>";
  }
}