Callback wrapper

[tshemsedinov]

Here is an idea of small but useful callback wrapper. After applying metasync.cb:

• no need to check like this: if (callback) return callback(err, data);
• wrapper prevents to call it more then once
• it may optionally add debugging wraper to trace async code (not for production) Usage:

  const doSomethingAsync = (par1, parN, callback) => {
  const cb = metasync.cb(callback); // apply wrapper
  // ... some code here ...
  // No need to check: if (cb) return ....
  cb(err, data); // first call will be passed to callback
  return cb(err, data); // second will write warning to console or log
  };

[tshemsedinov]

FYI: @aqrln

[tshemsedinov]

See: https://github.com/metarhia/MetaSync/issues/74 and https://github.com/metarhia/Common/issues/7