dep-time-travel.sh

#!/bin/bash

# expected: ESLINT_VERSION numeric env var

npm install --no-save eslint@$ESLINT_VERSION --ignore-scripts || true

# completely remove the new typescript parser for ESLint < v5
if [[ "$ESLINT_VERSION" -lt "5" ]]; then
  echo "Removing @typescript-eslint/parser..."
  npm uninstall @typescript-eslint/parser
fi

# use these alternate typescript dependencies for ESLint < v4
if [[ "$ESLINT_VERSION" -lt "4" ]]; then
  echo "Downgrading babel-eslint..."
  npm i --no-save babel-eslint@8.0.3

  echo "Downgrading TypeScript dependencies..."
  npm i --no-save typescript-eslint-parser@15 typescript@2.8.1
fi

# typescript-eslint-parser 1.1.1+ is not compatible with node 6
if [[ "$TRAVIS_NODE_VERSION" -lt "8" ]]; then
  echo "Downgrading eslint-import-resolver-typescript..."
  npm i --no-save eslint-import-resolver-typescript@1.0.2
fi