Merge pull request matplotlib#17026 from QuLogic/js-format

 Add eslint & prettier, and re-format JS

Author: timhoffm

.gitignore

@@ -104,3 +104,5 @@ lib/z.lib
 #########################
 
 jquery-ui-*/
+lib/matplotlib/backends/web_backend/node_modules/
+lib/matplotlib/backends/web_backend/package-lock.json

lib/matplotlib/backends/web_backend/.eslintrc.js

@@ -0,0 +1,21 @@
+module.exports = {
+  root: true,
+  ignorePatterns: ["jquery-ui-*/", "node_modules/"],
+  env: {
+    browser: true,
+    jquery: true,
+  },
+  extends: ["eslint:recommended", "prettier"],
+  globals: {
+    IPython: "readonly",
+    MozWebSocket: "readonly",
+  },
+  rules: {
+    "no-unused-vars": [
+      "error",
+      {
+        argsIgnorePattern: "^_",
+      },
+    ],
+  },
+};

lib/matplotlib/backends/web_backend/.prettierignore

@@ -0,0 +1,7 @@
+node_modules/
+
+# Vendored dependencies
+css/boilerplate.css
+css/fbm.css
+css/page.css
+jquery-ui-*/

lib/matplotlib/backends/web_backend/.prettierrc

@@ -0,0 +1,11 @@
+{
+  "overrides": [
+    {
+      "files": "js/**/*.js",
+      "options": {
+        "singleQuote": true,
+        "tabWidth": 4,
+      }
+    }
+  ]
+}