text: var annotate = require('annotate');
  var is = require('is-js');
      function zfill(amount, str) {
          var pad = '';
          str += '';
  
          while(pad.length < amount - str.length) pad += '0';
  
          return pad + str;
      }
  
      module.exports = annotate('zfill', 'Fills `string` beginning with the given `amount` of zeroes.')
          .on(is.number, zfill)
          .on(is.string, zfill);
  
  