Emulate Firebase functions locally

gistfile1.txt

-- 1. Downgrade node
-- Replace last line by 'sudo n stable' if you want to go back to the latest node version

sudo npm cache clean -f
sudo npm install -g n
sudo n 4.4.2 

-- 2. Install latest version of firebase-admin/functions 
-- On my side firebase-admin version = "^5.4.3" & firebase-functions version = "^0.7.1"
 
npm install --save firebase-admin@latest 
npm install --save firebase-functions@latest
 
--3. If error, uninstall/install firebase-tools
 
npm uninstall -g firebase-tools
npm install -g firebase-tools
 
--4. Ready to go, run following command in functions folder
 
firebase serve --only functions