Add linting and formatting for JS code in wasmtime explore

.github/workflows/js.yml

@@ -0,0 +1,25 @@
+name: JavaScript CI
+
+on:
+  pull_request
+    branches:
+    - main
+    - "release-*"
+
+# Cancel any in-flight jobs for the same PR/branch so there's only one active at
+# a time
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  check:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v4
+    - run: npm install
+      working-directory: ./crates/explorer
+    - run: npm run lint
+      working-directory: ./crates/explorer
+    - run: npm run fmt-check
+      working-directory: ./crates/explorer

.gitignore

@@ -23,3 +23,4 @@ vendor
 examples/build
 examples/.cache
 *.coredump
+crates/explorer/node_modules

crates/explorer/.prettierignore

@@ -0,0 +1,6 @@
+*.html
+*.css
+*.toml
+*.rs
+*.yml
+

crates/explorer/.prettierrc

@@ -0,0 +1,3 @@
+{
+  "arrowParens": "avoid"
+}

crates/explorer/eslint.config.js

@@ -0,0 +1,12 @@
+import js from "@eslint/js";
+
+export default [
+  js.configs.recommended,
+
+  {
+    rules: {
+      "no-unused-vars": "error",
+      "no-undef": "error",
+    },
+  },
+];