title: typescript parseInt not working as expected, receiving NaN
body: <p>i am tryng to parse a simple string to number but i am receiving NaN,</p>
  
  <p>The string is <code>"A20181"</code> ... i have been reading several post in diferents web but i dont find the solution...</p>
  
  <p>To parse a string to number in typescript, is like javascript right? i remember i did something similar and it was working, what i am doing wrong?</p>
  
  <pre><code>var text = 'A20181'
  var integer = parseInt(text, 10)
  
  console.log(integer) // receiving NaN....
  </code></pre>
  
  <p>how can i do this?</p>