Ionic Serve no longer working

I built my project in IOS and Android and since then Ionic Serve has stopped working. If I try the command I get this error:

Error opening the browser -  TypeError: s.replace is not a function
at escape (/usr/local/lib/node_modules/ionic/node_modules/open/lib/open.js:62:12)
at open (/usr/local/lib/node_modules/ionic/node_modules/open/lib/open.js:31:30)
at Object.openBrowser (/usr/local/lib/node_modules/ionic/node_modules/ionic-app-lib/lib/serve.js:240:7)
at /usr/local/lib/node_modules/ionic/node_modules/ionic-app-lib/lib/serve.js:510:15
at _fulfilled (/usr/local/lib/node_modules/ionic/node_modules/q/q.js:787:54)
at self.promiseDispatch.done (/usr/local/lib/node_modules/ionic/node_modules/q/q.js:816:30)
at Promise.promise.promiseDispatch (/usr/local/lib/node_modules/ionic/node_modules/q/q.js:749:13)
at /usr/local/lib/node_modules/ionic/node_modules/q/q.js:557:44
at flush (/usr/local/lib/node_modules/ionic/node_modules/q/q.js:108:17)
at _combinedTickCallback (internal/process/next_tick.js:67:7)

I have tried deleting the:

"defaultBrowser": true

line from the ionic.config.json file as recommended on another forum but it just seems to add it back when i try and serve, if it does work (which it does occasionally if I remove this line) I get some weird behaviour in that the version served is always Android native and no matter what I am unable to serve the IOS version. As a work around I am using Ionic Labs which still works fine however it is not ideal. A side effect to the issue is that now all of the .ts files within my app directory have been been compiles into seperate js files. While this does not affect the application itself it is extremely annoying. Any help would be greatly appreciated.

try: > ionic serve -b