[Refactor] split CI into eslint <= 8, and eslint >= 9

Author: ljharb

.github/workflows/node-18+.yml .github/workflows/eslint-8-.yml.github/workflows/node-18+.yml renamed to .github/workflows/eslint-8-.yml

@@ -1,4 +1,4 @@
-name: 'Tests: node.js (18+)'
+name: 'Tests: ESLint (8-)'
 
 on: [pull_request, push]
 
@@ -26,7 +26,6 @@ jobs:
       matrix:
         node-version: ${{ fromJson(needs.matrix.outputs.latest) }}
         eslint:
-          - 9
           - 8
           - 7
           - 6
@@ -64,8 +63,6 @@ jobs:
             typescript-eslint: 6
           - eslint: 6
             typescript-eslint: 6
-          - eslint: 9
-            typescript-eslint: 6
           - eslint: 3
             typescript-eslint: 7
           - eslint: 4
@@ -78,8 +75,6 @@ jobs:
             typescript-eslint: 7
           - eslint: 7
             typescript-eslint: 7
-          - eslint: 9
-            typescript-eslint: 7
           - eslint: 3
             typescript-eslint: 8
           - eslint: 4
@@ -92,8 +87,6 @@ jobs:
             typescript-eslint: 8
           - eslint: 7
             typescript-eslint: 8
-          - eslint: 9
-            typescript-eslint: 5
           - node-version: 19
             typescript-eslint: 7
 
@@ -112,7 +105,7 @@ jobs:
       - uses: codecov/codecov-action@v3.1.5
 
   node:
-    name: 'node 18+'
+    name: 'eslint 8-'
     needs: [latest]
     runs-on: ubuntu-latest
     steps:

.github/workflows/eslint-9+.yml

@@ -0,0 +1,48 @@
+name: 'Tests: ESLint (9+)'
+
+on: [pull_request, push]
+
+jobs:
+  matrix:
+    runs-on: ubuntu-latest
+    outputs:
+      latest: ${{ steps.set-matrix.outputs.requireds }}
+      minors: ${{ steps.set-matrix.outputs.optionals }}
+    steps:
+      - uses: ljharb/actions/node/matrix@main
+        id: set-matrix
+        with:
+          versionsAsRoot: true
+          type: majors
+          preset: '>=18'
+
+  latest:
+    needs: [matrix]
+    name: 'latest majors'
+    runs-on: ubuntu-latest
+
+    strategy:
+      fail-fast: false
+      matrix:
+        node-version: ${{ fromJson(needs.matrix.outputs.latest) }}
+        eslint:
+          - 9
+        babel-eslint:
+          - 10
+          - 9
+          - 8
+        typescript-eslint:
+          - 8
+
+    steps:
+      - uses: actions/checkout@v4
+      - uses: ljharb/actions/node/install@main
+        name: 'nvm install ${{ matrix.node-version }} && npm install'
+        with:
+          node-version: ${{ matrix.node-version }}
+          after_install: |
+            npm install --no-save "eslint@${{ matrix.eslint }}" "@typescript-eslint/parser@${{ matrix.typescript-eslint == 8 && 8.17 || matrix.typescript-eslint }}" "babel-eslint@${{ matrix.babel-eslint }}"
+          skip-ls-check: true
+      - run: npx ls-engines
+      - run: npm run unit-test
+      - uses: codecov/codecov-action@v3.1.5