title: Suppress Typescript warnings
body: <p>I have following typescript code:</p>
  
  <pre><code> private addBrowserNameAsCssClassToHtmlTag(): void {
    var rootElement = angular.element(document.querySelector("html"));
    if (this.isOpera()) {
      rootElement.addClass("opera-browser");
    } else if (this.isFirefox()) {
      rootElement.addClass("firefox-browser");
    } else if (this.isSafari()) {
      rootElement.addClass("safari-browser");
    } else if (this.isIE()) {
      rootElement.addClass("ie-browser");
    } else if (this.isChrome()) {
      rootElement.addClass("chrome-browser");
    }
  }
  
  private isOpera(): boolean {
    return (!!(&lt;any&gt;window).opr &amp;&amp; !!(&lt;any&gt;opr).addons) || !!window.opera || navigator.userAgent.indexOf(' OPR/') &gt;= 0;
  }
  
  private isFirefox(): boolean {
    //noinspection TypeScriptUnresolvedVariable
    return typeof InstallTrigger !== 'undefined';
  }
  
  private isSafari(): boolean {
    return /constructor/i.test(window.HTMLElement) || ((p): boolean =&gt; {
        return p.toString() === "[object SafariRemoteNotification]";
      })(!window['safari'] || safari.pushNotification);
  }
  
  private isIE(): boolean {
    return /*@cc_on!@*/false || !!window.document.documentMode;
  }
  
  private isChrome(): boolean {
    return !!window.chrome &amp;&amp; !!window.chrome.webstore;
  }
  </code></pre>
  
  <p>Code works fine but the problem is that it generates compile time errors:</p>
  
  <pre><code>error TS2304: Cannot find name 'opr'.
  error TS2339: Property 'opera' does not exist on type 'Window'.
  error TS2304: Cannot find name 'InstallTrigger'.
  error TS2339: Property 'HTMLElement' does not exist on type 'Window'.
  error TS2304: Cannot find name 'safari'.
  error TS2339: Property 'documentMode' does not exist on type 'Document'.
  error TS2339: Property 'chrome' does not exist on type 'Window'.
  error TS2339: Property 'chrome' does not exist on type 'Window'.
  </code></pre>
  
  <p>If I wrote in plain javascript I wouldn't have any problem. How can I suppress compiler warnings concerning this part of code? Or maybe there is better solution which I don't know?</p>