npm install suddenly fails

I have been able to install node modules locally in a project for quite some time. All of sudden ALL attempts at installation fail, with the same type of error:

Homers-MacBook-Pro:test homer$ npm install bootstrap@3
/Users/homer
└── bootstrap@3.3.7 

npm WARN enoent ENOENT: no such file or directory, open '/Users/homer/package.json'
npm WARN homer No description
npm WARN homer No repository field.
npm WARN homer No README data
npm WARN homer No license field.                     

I'm not using a package.json file, just hoping to install some modules in a local node-modules directory. I don't understand why npm suddenly thinks it needs a package,json in my Home directory.

I'm on MacOS 10.12.4. There have been no upgrades in the system or in Node since the last successful npm install a couple of weeks ago.

via Homer White