title: How to implement CanActivate guard in Angular2
body: <p>I am trying to implement "CanActivate" method in my service, and below is the
  service code</p>
  
  <pre><code>import { Injectable } from '@angular/core';
  import { CanActivate } from '@angular/router';
  
  @Injectable()
  export class GuardUserSearchService implements CanActivate {
  
      CanActivate() {
          console.log('dummy guard clause for User search');
          return true;
      }
  }
  </code></pre>
  
  <p>When I compile this typeScript code , it is displays following error</p>
  
  <blockquote>
    <p>Class 'GuardUserSearchService' incorrectly implements interface 'CanActivate'.</p>
  </blockquote>
  
  <p>Any idea what is the issue in my code.</p>