title: Default value for each type in typescript
body: <p>Where can I find the default value of each type in typescript? For example, where is mentioned the default value for <code>number</code> type is <code>null</code> or <code>0.</code>? Or about the <code>string</code>?</p>
  <p>The default value means the value of a variable that is defined, but not assigned. Like <code>let a : number;</code>. This happens a lot in object definitions. For example:</p>
  <pre><code> class A{
       let a: number;
       let b: string;
   }
   let obj: A;
  </code></pre>
  <p>Therefore, the question is on the values of <code>a</code> and <code>b</code> for <code>obj</code>.</p>