I just installed Visual Studio 2017 and opened a solution I had been working in with Visual Studio 2015. It seems like everything works great except that the task runner explorer in VS 2017 is not detecting the package.json file in one of my projects so it is giving me the message "No task runner configurations were found." My package.json is in the same folder as my solution file and I added it into the proper project by creating a file link. VS 2015 had no problem with this and I'm not sure why VS 2017 does or how to fix it.
I found the NPM Task Runner extension in the Visual Studio Marketplace that fixed my problem. After installing it, the package.json file showed up in Task Runner Explorer.
Also, don't forget to set your system path to be the top priority for the External Web Tools by going into Options > External Web Tools and moving $(PATH) up the list. My npm scripts were failing until I did this as well.