Added rule to handle sessionStorage and localStorage

.changeset/long-singers-help.md

@@ -0,0 +1,13 @@
+---
+"@total-typescript/ts-reset": minor
+---
+
+Added a rule, `/session`, to make sessionStorage and localStorage safer.
+
+```ts
+// Is now typed as `unknown`, not `any`!
+localStorage.a;
+
+// Is now typed as `unknown`, not `any`!
+sessionStorage.abc;
+```

.changeset/wise-cycles-jam.md

@@ -0,0 +1,5 @@
+---
+"@total-typescript/ts-reset": minor
+---
+
+Added a `/dom` entrypoint to allow users to import DOM-only rules.

package.json

@@ -72,6 +72,16 @@
       "types": "./dist/array-index-of.d.ts",
       "import": "./dist/array-index-of.mjs",
       "default": "./dist/array-index-of.js"
+    },
+    "./dom": {
+      "types": "./dist/dom.d.ts",
+      "import": "./dist/dom.mjs",
+      "default": "./dist/dom.js"
+    },
+    "./storage": {
+      "types": "./dist/storage.d.ts",
+      "import": "./dist/storage.mjs",
+      "default": "./dist/storage.js"
     }
   },
   "keywords": [],

readme.md

@@ -36,6 +36,19 @@ fetch("/")
   });
 ```
 
+### DOM Example
+
+```ts
+// Import from /dom to get DOM rules too!
+import "@total-typescript/ts-reset/dom";
+
+// localStorage just got safer!
+localStorage.abc; // unknown
+
+// sessionStorage just got safer!
+sessionStorage.abc; // unknown
+```
+
 ## Get Started
 
 1. Install: `npm i -D @total-typescript/ts-reset`
@@ -293,6 +306,27 @@ const validate = (input: unknown) => {
 };
 ```
 
+### Making `sessionStorage` and `localStorage` safer
+
+By default, `localStorage` and `sessionStorage` let you access any key, and return `any`:
+
+```ts
+// BEFORE
+
+// No error!
+localStorage.a.b.c.ohDear; // any
+```
+
+With this rule enabled, these keys now get typed as `unknown`:
+
+```ts
+// AFTER
+import "@total-typescript/ts-reset/storage";
+
+// Error!
+localStorage.a.b.c.ohDear;
+```
+
 ## Rules we won't add
 
 ### `Object.keys`/`Object.entries`

src/entrypoints/dom.d.ts

@@ -0,0 +1,2 @@
+/// <reference path="recommended.d.ts" />
+/// <reference path="storage.d.ts" />

src/entrypoints/storage.d.ts

@@ -0,0 +1,3 @@
+interface Storage {
+  [name: string & {}]: unknown;
+}

src/tests/storage.ts

@@ -0,0 +1,47 @@
+import { doNotExecute, Equal, Expect } from "./utils";
+
+// Ensure that arbitrary access to localStorage is not allowed
+doNotExecute(() => {
+  type test = Expect<Equal<typeof localStorage.a, unknown>>;
+
+  // @ts-expect-error
+  localStorage.a.b.c;
+});
+
+// Ensure that the type of localStorage remains correct
+doNotExecute(() => {
+  type tests = [
+    Expect<Equal<typeof localStorage.getItem, (key: string) => string | null>>,
+    Expect<
+      Equal<typeof localStorage.setItem, (key: string, value: string) => void>
+    >,
+    Expect<Equal<typeof localStorage.removeItem, (key: string) => void>>,
+    Expect<Equal<typeof localStorage.clear, () => void>>,
+    Expect<Equal<typeof localStorage.key, (index: number) => string | null>>,
+    Expect<Equal<typeof localStorage.length, number>>,
+  ];
+});
+
+// Ensure that arbitrary access to sessionStorage is not allowed
+doNotExecute(() => {
+  type test = Expect<Equal<typeof sessionStorage.a, unknown>>;
+
+  // @ts-expect-error
+  sessionStorage.a.b.c;
+});
+
+// Ensure that the type of sessionStorage remains correct
+doNotExecute(() => {
+  type tests = [
+    Expect<
+      Equal<typeof sessionStorage.getItem, (key: string) => string | null>
+    >,
+    Expect<
+      Equal<typeof sessionStorage.setItem, (key: string, value: string) => void>
+    >,
+    Expect<Equal<typeof sessionStorage.removeItem, (key: string) => void>>,
+    Expect<Equal<typeof sessionStorage.clear, () => void>>,
+    Expect<Equal<typeof sessionStorage.key, (index: number) => string | null>>,
+    Expect<Equal<typeof sessionStorage.length, number>>,
+  ];
+});