Possible Solution:

1. Some has try the following:

npm install –no-optional

2. Others have downgraded to npm 5.3.

npm install npm@5.3 -g

3. Remove npm and npm cache

C:\Users\your.name\AppData\Roaming\npm
C:\Users\your.name\AppData\Roaming\npm-cache

But none of the above works for me.

4. The hard way is to rollback and start with a working state.

5. Finally, if none of above works, start a new app and slowly migrate over to see what changes cause the issue. This is a tedious and long process.