lerna_lint_test_copy.md

Using Lerna to Lint, Test and Copy NPM packages

Lerna allows you to list local packages that have changed since the last release:

$ cd /path/to/node-app
$ npx lerna changed -p

lerna notice cli v3.20.2
lerna info versioning independent
lerna info Looking for changed packages since @fedecarg/template@4.0.17
/path/to/node-app/packages/analytics
/path/to/node-app/packages/breaking-news
/path/to/node-app/packages/footer
/path/to/node-app/packages/header
/path/to/node-app/packages/template
/path/to/node-app/packages/user-account
lerna success found 6 packages ready to publish

You can use a combination of lerna changed and lerna exec to lint and test only the packages that changed.

For example:

Lint:

$ npx lerna exec $(for package_dir in `npx lerna changed -p`; do echo -n " --scope @fedecarg/$(basename ${package_dir})"; done) -- yarn lint

Test:

$ npx lerna exec $(for package_dir in `npx lerna changed -p`; do echo -n " --scope @fedecarg/$(basename ${package_dir})"; done) -- npm test -- --no-watch --passWithNoTests

You can also use Lerna to build packages that changed in node-app and copy them to any consuming app:

Copy:

1. Change directory to node-app:

$ cd /path/to/node-app

2. Commit all the changed files and push to remote:

git add .
git commit -m "Commit message"
git push origin <branch>

3. Set the destination path to the consuming app:

$ DESTINATION_PATH=/path/to/consuming_app/node_modules/@fedecarg

4. Build and copy packages:

$ for package_dir in `npx lerna changed -p`; do \
  yarn --cwd ${package_dir} build && \
  rm -Rf "${DESTINATION_PATH}/$(basename ${package_dir})" && \
  cp -R ${package_dir} ${DESTINATION_PATH} && \
  echo "Copied ${package_dir}..."; \
done