sudo: false
language: node_js
node_js:
  - "4"
  - "6"
  - "8"
  - "10"
after_script: NODE_ENV=test istanbul cover ./node_modules/mocha/bin/_mocha --report lcovonly -- -R spec && cat ./coverage/lcov.info | ./node_modules/coveralls/bin/coveralls.js && rm -rf ./coverage

sudo: false
language: node_js
node_js:
  - "6"
  - "8"
  - "10"
after_script: NODE_ENV=test istanbul cover ./node_modules/mocha/bin/_mocha --report lcovonly -- -R spec && cat ./coverage/lcov.info | ./node_modules/coveralls/bin/coveralls.js && rm -rf ./coverage

Drop Node.js 4 from build
Drop Node.js 4 from build

It's end-of-life since April 2018.
