Web Storage: getItem()

The getItem() method returns the string saved under a key, or null when that key does not exist.

const theme = localStorage.getItem('theme') ?? 'light';

Choose a sensible default for a missing value. If you stored JSON, parse it only after checking that the string has the expected shape.

Common mistakes

• Do not confuse the string 'null' with the value null.
• Validate stored data because users or older versions of your app may have written it.
• Remember that storage can be unavailable.