title: Why does TypeScript allow to compile?
body: <p>There are two simple TypeScript codes.</p>
  
  <p>a.ts</p>
  
  <pre><code>console.log(name);
  </code></pre>
  
  <p>b.ts</p>
  
  <pre><code>console.log(a);
  </code></pre>
  
  <p>a.ts can be compiled, but compiler complains for b.ts</p>
  
  <pre><code>$ ./node_modules/.bin/tsc a.ts
  $ ./node_modules/.bin/tsc b.ts
  b.ts(1,13): error TS2304: Cannot find name 'a'.
  </code></pre>
  
  <p>Why can a.ts be succeeded?
  I'm really confused.</p>
  
  <p>I'm using v2.0.10</p>
  
  <pre><code>$ ./node_modules/.bin/tsc --version
  Version 2.0.10
  </code></pre>
  
  <p>Best,</p>