Node 10.0.0 yields an unexpected result when functions are converted to strings through the toString method. Here's what happens:

• 10.0.0: (function () { }).toString() results in: 'function () { }'.
• 9.5.0: (function(){ }).toString() results in: 'function (){ }'.

The affected line is: https://github.com/nodegit/promisify-node/blob/master/utils/args.js#L9
A possible solution is to change the RegExp to: /function.*?\(([^)]*)\)/ (for example).