ci: create npm workspaces and sort out dependencies

This requires at least npm v7.

Reference: https://docs.npmjs.com/cli/v10/using-npm/workspaces

Note: @types/node is pinned at `18.15.3` because it's the last version
which supports TypeScript v4.2.

Author: darrachequesne

.github/workflows/ci.yml

@@ -32,14 +32,16 @@ jobs:
       - name: Install dependencies
         run: npm ci
 
+      # in order to test our compliance with TypeScript v4.2 (older versions are not tested)
       - name: Install TypeScript 4.2
         run: npm i [email protected]
         if: ${{ matrix.node-version == '16' }}
 
+      - name: Compile each package
+        run: npm run compile --workspaces
+
       - name: Run tests
-        run: npm test
-        env:
-          CI: true
+        run: npm test --workspaces
 
   build-examples:
     runs-on: ubuntu-latest

.gitignore

@@ -12,3 +12,4 @@ coverage
 .idea
 .nyc_output
 dist/
+build/