title: Define typescript class method
body: <p>I cannot find any information about "declaration and then initialization" of class method, for example can I do this (code below), first declare <code>getName()</code> and then initialize it, tslint tips me that I cannot do this, then what I should do, if doesn't want construction, like <code>public getName(name: string): string { return this.name }</code>?</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-js lang-js prettyprint-override"><code>class Cat {
    public getName(name: string): string;
    
    constructor() { ... }
    
    getName(name) {
      return this.name;
    }
  }</code></pre>
  </div>
  </div>
  </p>