upgrade node to v12 code example

Example 1: update nodejs

//First, clear the npm cache:
	npm cache clean -f

//Install n, Node’s version manager:
	npm install -g n
    
//With the n module installed, you can use it to:
	Install the latest stable version: n stable
	Install the latest release: n latest

Example 2: Please update your node with version 8.11.3 or greater (but not version 10)

nvm install v14.15.0