Impossible Regular Expressions

expressions.js

/* These are regular expressions that will
never be matched by any string ever */

[
  // http://stackoverflow.com/a/1845111
  /$./,
  
  // http://stackoverflow.com/a/1845097
  /(?!x)x/,
  
  // http://stackoverflow.com/a/1723264
  /(?=a)b/,
  
  // http://stackoverflow.com/a/1845111
  /(?!)/,
  
  // http://stackoverflow.com/a/4850260
  /\B\b/,
];