introduce api-extractor

.github/workflows/api.yml

@@ -0,0 +1,40 @@
+name: API report
+
+on: [push, pull_request]
+
+jobs:
+  report:
+
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v1
+        with:
+          node-version: 16.5.0
+
+      - name: Cache dependencies
+        uses: actions/cache@v2
+        with:
+          path: ~/.npm
+          key: npm-${{ hashFiles('package-lock.json') }}
+          restore-keys: npm-
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Build
+        run: npm run build
+
+      - name: Check files
+        run: ls built
+
+      - name: API report
+        run: npm run api-prod
+
+      - name: Show report
+        if: always()
+        run: cat temp/aiscript.api.md