eslint-plugin-safely-storage


Summary

Access to Web Storage API (sessionStorage or localStorage) can cause an exception in some user environments, so be sure to use it with try...catch.

- If the user blocks cookies in the browser settings (SecurityError)
- In setItem() method, if the storage run out of disk quota (QuotaExceededError)

``javascript
try {
const storageKey = 'foo';

sessionStorage.clear();
sessionStorage.setItem(storageKey, 'x'.repeat(5242880 - storageKey.length + 1)); // Set data exceeding 5MB
} catch (e) {
if (e instanceof DOMException) {
console.warn(e.name); // SecurityError if cookies are blocked, otherwise QuotaExceededError
}
}
`

After applying this plugin, an error will occur in places where try...catch is not used.

`javascript
/ 🆖 /
const foo = sessionStorage.getItem('foo');

doSomething(); // This process will not be reached if the browser blocks cookies
`

`javascript
/ 🆗 /
try {
const foo = sessionStorage.getItem('foo');
} catch {}

doSomething(); // This process will run even if the browser blocks cookies
`

`javascript
/ 🆗 /
let mySessionStorage;
try {
mySessionStorage = sessionStorage;
} catch {}

const foo = mySessionStorage?.getItem('foo');

doSomething(); // This process will run even if the browser blocks cookies
`

Usage

`javascript
import js from '@eslint/js';
import pluginSafelyStorage from 'eslint-plugin-safely-storage';
import globals from 'globals';

/* @type {import('eslint').Linter.Config[]} /
export default [
js.configs.recommended,
...pluginSafelyStorage.configs.default,
{
languageOptions: {
globals: {
...globals.browser,
},
},
},
];
``