eslint-plugin-safely-storage v1.0.2

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)

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.

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

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

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

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

/* 🆗 */
let mySessionStorage;
try {
  mySessionStorage = sessionStorage;
} catch {}

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

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

Usage

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,
      },
    },
  },
];