chore: apply eslint to wordcloud2

.eslintrc.js

@@ -0,0 +1,29 @@
+/**
+ * Using StandardJS for the ES6 environment. All rules are documented at:
+ * https://standardjs.com/
+ *
+ * Extending configuration from eslint-config-standard:
+ * https://github.com/standard/eslint-config-standard/blob/master/eslintrc.json
+ *
+ * We extend the standard configuration with our own globals, parser,
+ * and environment for shared needs of all repos.
+ *
+ * Do NOT add/modify any rules. We are adhering strictly to rules set by the
+ * StandardJS community. If any exceptions are truly needed, they can be
+ * made by consuming repos with their own respective eslintrc config files.
+ */
+
+module.exports = {
+  env: {
+    es6: true,
+    browser: true
+  },
+  rules: {
+    // Workaround for optional chaining, remove once https://github.com/eslint/eslint/issues/12822 is fixed
+    'no-unused-expressions': 'off'
+  },
+  ignorePatterns: [
+    './.eslintrc.js',
+    '**/*/node_modules/'
+  ]
+}

lefthook.yml

@@ -0,0 +1,46 @@
+# EXAMPLE USAGE
+# Refer for explanation to following link:
+# https://github.com/Arkweid/lefthook/blob/master/docs/full_guide.md
+#
+# pre-push:
+#   commands:
+#     packages-audit:
+#       tags: frontend security
+#       run: yarn audit
+#     gems-audit:
+#       tags: backend security
+#       run: bundle audit
+#
+# pre-commit:
+#   parallel: true
+#   commands:
+#     eslint:
+#       glob: "*.{js,ts}"
+#       run: yarn eslint {staged_files}
+#     rubocop:
+#       tags: backend style
+#       glob: "*.rb"
+#       exclude: "application.rb|routes.rb"
+#       run: bundle exec rubocop --force-exclusion {all_files}
+#     govet:
+#       tags: backend style
+#       files: git ls-files -m
+#       glob: "*.go"
+#       run: go vet {files}
+#   scripts:
+#     "hello.js":
+#       runner: node
+#     "any.go":
+#       runner: go run
+
+pre-commit:
+  parallel: true
+  commands:
+    eslint:
+      glob: "*.{js,ts}"
+      run: npm run lint {staged_files}
+
+post-merge:
+  commands:
+    yarn-install:
+      run: yarn --frozen-lockfile