Add ESLint plugin to check React hooks usage

Usage of "hooks" has to follow certain rules [1]. This adds the official
ESLint plugin to check for this.

All the checks are marked as errors following the "no warnings, only
errors" principle. ESLint suppressions can be used to ignore any cases
where we decide not to follow a "rule".

[1] https://reactjs.org/docs/hooks-rules.html

.eslintrc

@@ -9,7 +9,9 @@
   "rules": {
     "mocha/no-exclusive-tests": "error",
     "no-var": "error",
-    "indent": "off"
+    "indent": "off",
+    "react-hooks/rules-of-hooks": "error",
+    "react-hooks/exhaustive-deps": "error"
   },
   "parserOptions": {
     "ecmaVersion": 2018,
@@ -19,7 +21,8 @@
   },
   "plugins": [
     "mocha",
-    "react"
+    "react",
+    "react-hooks"
   ],
   "settings": {
     "react": {

package.json

@@ -54,6 +54,7 @@
     "eslint-config-hypothesis": "^1.0.0",
     "eslint-plugin-mocha": "^5.2.1",
     "eslint-plugin-react": "^7.12.4",
+    "eslint-plugin-react-hooks": "^1.6.0",
     "exorcist": "^1.0.1",
     "express": "^4.14.1",
     "extend": "^3.0.2",

scripts/.eslintrc

@@ -4,6 +4,7 @@
   },
   "rules": {
     "no-console": "off",
+    "react-hooks/rules-of-hooks": "off"
   },
   "parserOptions": {
     "ecmaVersion": 2018

yarn.lock

@@ -3724,6 +3724,11 @@ eslint-plugin-mocha@^5.2.1:
   dependencies:
     ramda "^0.26.1"
 
+eslint-plugin-react-hooks@^1.6.0:
+  version "1.6.0"
+  resolved "https://registry.yarnpkg.com/eslint-plugin-react-hooks/-/eslint-plugin-react-hooks-1.6.0.tgz#348efcda8fb426399ac7b8609607c7b4025a6f5f"
+  integrity sha512-lHBVRIaz5ibnIgNG07JNiAuBUeKhEf8l4etNx5vfAEwqQ5tcuK3jV9yjmopPgQDagQb7HwIuQVsE3IVcGrRnag==
+
 eslint-plugin-react@^7.12.4:
   version "7.12.4"
   resolved "https://registry.yarnpkg.com/eslint-plugin-react/-/eslint-plugin-react-7.12.4.tgz#b1ecf26479d61aee650da612e425c53a99f48c8c"