You can know if you shold npm install.

needs-pkg-install compares dependency versions in package-lock.json and actually installed library versions in node_modules directory, and returns true if found differences.

$ npm install needs-pkg-install

const needsPkgInstall = require('needs-pkg-install')

const packageDirectory = '.'
needsPkgInstall(packageDirectory).then(console.log)
// true or false