eslint: Add custom rules

James went through all the rules that we had custom-enabled prior to
b3cedb7. These are the ones that were
flagged to be re-added.

Some are commented out since there are existing violations. Subsequent
commits will un-comment the rules and address violations.

Co-authored-by: James Hadfield <hadfield.james@gmail.com>

.eslintrc.yaml

@@ -20,9 +20,15 @@ globals:
 rules:
   # Code quality rules
   no-unused-vars: ["error", { "argsIgnorePattern": "^_", "destructuredArrayIgnorePattern": "^_" }]
+  # no-use-before-define: ["error", { "functions": false }]
+  # prefer-const: ["error", {"destructuring": "all"}]
   react/prop-types: off # Remove this override once all props have been typed using PropTypes or TypeScript.
 
   # Code style rules
+  arrow-parens: ["error", "always"]
+  # no-unneeded-ternary: ["error", { "defaultAssignment": true }]
+  operator-linebreak: ["error", "after", { "overrides": { "?": "ignore", ":": "ignore" } }]
+  quote-props: ["error", "as-needed"]
 
 parserOptions:
   ecmaVersion: 6

src/.eslintrc.yaml

@@ -2,3 +2,6 @@
 
 rules:
   react/jsx-filename-extension: [1, { "extensions": [".js", ".jsx"] }]
+
+  # Code quality rules
+  # no-console: [1, { "allow": ["warn", "error"] }]