JSON error when installing vue/cli via npm - node.js

Question

I'm receiving these warnings when I run npm i -g #vue/cli - how can I investigate and fix the problem?
npm WARN deprecated #hapi/joi#15.1.1: joi is leaving the #hapi organization and moving back to 'joi' (https://github.com/sideway/joi/issues/2411)
npm WARN deprecated request#2.88.2: request has been deprecated, see https://github.com/request/request/issues/3142
npm WARN deprecated #hapi/bourne#1.3.2: This version has been deprecated and is no longer supported or maintained
npm WARN deprecated #hapi/address#2.1.4: This version has been deprecated and is no longer supported or maintained
npm WARN deprecated #hapi/hoek#8.5.1: This version has been deprecated and is no longer supported or maintained
npm WARN deprecated #hapi/topo#3.1.6: This version has been deprecated and is no longer supported or maintained
npm WARN deprecated har-validator#5.1.5: this library is no longer supported
npm ERR! Unexpected end of JSON input while parsing near '...omposition":"6.0.1-al'
npm ERR! A complete log of this run can be found in:
npm ERR! C:\Users\Micheal\AppData\Roaming\npm-cache\_lo

Answer 1

The error you have received here is:
Unexpected end of JSON input while parsing near '...omposition":"6.0.1-al'
This error means that a file contains invalid JSON, but it doesn't tell you which file it is.
However, because this is npm, the most likely candidate is package.json - search in that file for "6.01-al" and see if you can find the error. This is almost always caused by manually editing the dependencies in your package.json file.
In this case, it looks like the error is that a file has been truncated, in which case it could be one of the packages you are installing, that has failed to download properly or might have been corrupted en-route. Try installing the package on another machine if you can.