title: How to check if two strings are almost equal with Angular
body: <p>I have a quiz app made with Ionic and Angular 4. User have to submit answer, I check if it's the same as the good answer or not.
  I would like to check string correspondence, and handle event according to the correspondence between good answer and user answer. </p>
  
  <p>In Exemple :
  If the answer is 'azerty', and he wrote 'mzerty', I would like to allow him to continue.
  If user wrote 'qwerty', or something too different, he failes.</p>