promised-exponential-backoff.js

function exponentialBackoff(toTry, max, delay, callback) {
    new Promise(function(resolve, reject) {
      // do a thing then…
      var ret = toTry.toString();
      ret = ret.substr('function '.length);
      ret = ret.substr(0, ret.indexOf('('));
      console.log('EB '+ret+' max',max,'next delay',delay);
      var result = toTry();
      
      if (result) {
          resolve(true);
      } else {
          if (max > 0) {
              setTimeout(function() {
                  exponentialBackoff(toTry, --max, delay * 2, callback);
              }, delay);

          } else {
               console.log('and I\'m giving up now...');
               resolve(false);
               
          }
      }
    }).then(function(result){
      callback(result);
    });  	
}