chore: setup new linting rule

Author: RebeccaStevens

.eslintrc.json

@@ -30,6 +30,14 @@
   "rules": {
     "@typescript-eslint/no-unnecessary-condition": "off",
     "import/no-relative-parent-imports": "error",
+    "functional/prefer-readonly-type": "off",
+    "functional/prefer-readonly-type-declaration": ["error", {
+      "aliases": {
+        "mustBeMutable": {
+          "requireOthersToBeReadonly": false
+        }
+      }
+    }],
     "node/no-unsupported-features/es-builtins": "off",
     "node/no-unsupported-features/es-syntax": "off",
     // enable once supported in all our supported node versions.

tests/helpers/util.ts

@@ -83,9 +83,7 @@ export function createDummyRule(
 }
 
 export type RuleTesterTests = {
-  // eslint-disable-next-line functional/prefer-readonly-type
   valid?: Array<ESLintRuleTester.ValidTestCase | string>;
-  // eslint-disable-next-line functional/prefer-readonly-type
   invalid?: Array<ESLintRuleTester.InvalidTestCase>;
 };