diff --git a/.eslintrc.json b/.eslintrc.json
index 3563858..ca3aba9 100644
--- a/.eslintrc.json
+++ b/.eslintrc.json
@@ -10,7 +10,8 @@
     "ecmaVersion": 2017
   },
   "rules": {
-    "no-shadow": "error",
-    "no-magic-numbers": "error"
+    "no-shadow": "warn",
+    "no-magic-numbers": "warn",
+    "no-param-reassign": "warn"
   }
 }
diff --git a/.prettierrc.yml b/.prettierrc.yml
index a785dbb..194b624 100644
--- a/.prettierrc.yml
+++ b/.prettierrc.yml
@@ -2,6 +2,7 @@ trailingComma: 'es5'
 tabWidth: 2
 semi: true
 singleQuote: true
+arrowParens: always
 printWidth: 80
 overrides:
   - files: '*.svelte'
diff --git a/tslint.json b/tslint.json
index 7301352..b474f86 100644
--- a/tslint.json
+++ b/tslint.json
@@ -4,18 +4,27 @@
   "defaultSeverity": "warn",
   "rules": {
     "prettier": true,
+    "typedef": [
+      true,
+      "arrow-call-signature",
+      "arrow-parameter",
+      "call-signature",
+      "member-variable-declaration",
+      "parameter",
+      "property-declaration"
+    ],
     "no-console": true,
     "object-literal-sort-keys": [true, "match-declaration-order-only"],
     "no-implicit-dependencies": false,
     "no-submodule-imports": false,
-    "arrow-parens": [true, "ban-single-arg-parens"],
     "no-floating-promises": true,
     "no-unused-expression": true,
     "await-promise": true,
     "no-inferrable-types": true,
     "prefer-for-of": true,
     "no-empty": [true, "allow-empty-functions"],
-    "no-magic-numbers": true
+    "no-magic-numbers": true,
+    "no-parameter-reassignment": true
   },
   "jsRules": true
 }