Update the ESLint config to v8 (#65)

The ESLint config has been updated to v8. The lint scripts have been
updated to match the MetaMask module template, and all lint errors
have been fixed.

The config wasn't updated to v9 because that would involve writing
comments for everything. That can wait for a later PR, since all of
those manual changes would be difficult to review when mixed in with
these changes (which are mostly automatic fixes).

Most of the manual lint fixes were pretty straightforward, but one
notable case was the use of the bitwise OR operator. I saw that `| 0`
was used in a few different places to truncate anything after the
decimal point. `Math.floor` is now used instead, as it achieves the
same effect and is easier to understand.

.eslintrc.js

@@ -1,24 +1,18 @@
 module.exports = {
-  env: {
-    es6: true,
-    browser: true,
-  },
-  extends: [
-    '@metamask/eslint-config',
-    '@metamask/eslint-config/config/nodejs',
+  root: true,
+
+  extends: ['@metamask/eslint-config', '@metamask/eslint-config-nodejs'],
+
+  overrides: [
+    {
+      files: ['./example/*.js', './index.js', './util.js'],
+      globals: {
+        Blob: true,
+        document: true,
+        window: true,
+      },
+    },
   ],
-  plugins: [
-    'json',
-  ],
-  parserOptions: {
-    ecmaVersion: 2018,
-  },
-  ignorePatterns: [
-    '!.eslintrc.js',
-    'node_modules/',
-    'bundle.js',
-  ],
-  rules: {
-    'no-bitwise': 'off',
-  },
-}
+
+  ignorePatterns: ['!.eslintrc.js', '!.prettierrc.js', 'bundle.js'],
+};

.gitignore

@@ -1,5 +1,5 @@
-
-# Created by https://www.gitignore.io/api/osx,node
+# Optional eslint cache
+.eslintcache
 
 ### OSX ###
 .DS_Store

.prettierrc.js

@@ -0,0 +1,8 @@
+// All of these are defaults except singleQuote, but we specify them
+// for explicitness
+module.exports = {
+  quoteProps: 'as-needed',
+  singleQuote: true,
+  tabWidth: 2,
+  trailingComma: 'all',
+};

README.md

@@ -10,11 +10,10 @@ The sample app javascript is `bundle.js`, which is built from `sample.js` using
 ## API
 
 ```javascript
-const ModelViewer = require('@metamask/logo')
+const ModelViewer = require('@metamask/logo');
 
 // To render with fixed dimensions:
 const viewer = ModelViewer({
-
   // Dictates whether width & height are px or multiplied
   pxNotRatio: true,
   width: 500,
@@ -28,24 +27,23 @@ const viewer = ModelViewer({
 
   // head should slowly drift (overrides lookAt)
   slowDrift: false,
-
-})
+});
 
 // add viewer to DOM
-const container = document.getElementById('logo-container')
-container.appendChild(viewer.container)
+const container = document.getElementById('logo-container');
+container.appendChild(viewer.container);
 
 // look at something on the page
 viewer.lookAt({
   x: 100,
   y: 100,
-})
+});
 
 // enable mouse follow
-viewer.setFollowMouse(true)
+viewer.setFollowMouse(true);
 
 // deallocate nicely
-viewer.stopAnimation()
+viewer.stopAnimation();
 ```
 
 ## Running Example