Cordova + Ionic installation error using Node.js

Question

In the attempt to install Cordova + Ionic using Node.js, the following error is occurring:

npm ERR! Windows_NT 6.1.7601
npm ERR! argv "C:\\Program Files\\nodejs\\node.exe" "C:\\Program Files\\nodejs\\
node_modules\\npm\\bin\\npm-cli.js" "install" "-g" "cordova" "ionic"
npm ERR! node v6.9.4
npm ERR! npm  v3.10.10
npm ERR! code UNABLE_TO_VERIFY_LEAF_SIGNATURE

npm ERR! unable to verify the first certificate
npm ERR!
npm ERR! If you need help, you may report this error at:
npm ERR!     <https://github.com/npm/npm/issues>

npm ERR! Please include the following file with any support request:
npm ERR!     C:\Users\blablabla\npm-debug.log

Apparently the most relevant line is this below:

code UNABLE_TO_VERIFY_LEAF_SIGNATURE

What would be the real cause of the error? How can it be solved?

Answer 1

Try to clear the cache and run the commands again:

npm cache clean
npm install -g cordova ionic