Testing multiple major versions of NPM modules

test.sh

#!/bin/bash -e

# $0 - Required module name
# $1 - Optional minimum version

module=$1

# Assert we have a module to install
: ${module:?}

# Get the range of versions to test against
read minVersion headVersion <<< $(
  cat package.json \
    | grep "\"$module\"" \
    | cut -d '"' -f 4 \
    | sed 's/\^//; s/~//; s/>//; s/<//; s/=//; s/[[:space:]]//' \
    | cut -d '.' -f 1 \
    | sort -n
)

# Use given minimum version to test against
if [ ! -z "$2" ]; then
  minVersion=$2
fi

# Assert we have a current version to test against and reset to
: ${headVersion:?}

# Assert we have a minimum version to test against
: ${minVersion:?}

# Do the work
for((version=$headVersion; version >= $minVersion; version--)) do
  # Install specific version to test against
  npm install $module@$version

  # Get installed version from disk
  installedVersion=$(
    npm ls $module --depth 0 /dev/null \
      | grep $module \
      | cut -d '@' -f 2 \
      | cut -d '.' -f 1
  )

  # Assert that the version we want to test was actually installed
  if [ "$version" -ne "$installedVersion" ]; then exit 1; fi

  # Run tests
  docker-compose run comm_disrupted npm run test
done

# Reset to version from package.json
npm install $module@$headVersion