SharedStorage: append() method

The append() method of the SharedStorage interface appends a string to the value of an existing key-value pair in the current origin’s shared storage.

Syntax

append(key, value)

Parameters

• key
  • : A string representing the key of the key-value pair to which you want to append a value.
• value
  • : A string that you want to append to the existing value of the key-value pair.

[!NOTE] If the specified key isn’t found in the shared storage, the append() operation is equivalent to set(), that is, a new key-value pair with the specified key is added to the shared storage.

Return value

A Promise that fulfills with undefined.

Exceptions

• The Promise rejects with a TypeError if:
  • The appended entry was not successfully stored in the database due to shared storage not being available (for example it is disabled using a browser setting).
  • key and/or value exceed the browser-defined maximum length.
  • The calling site does not have the Shared Storage API included in a successful privacy sandbox enrollment process.
• In the case of WorkletSharedStorage, the Promise rejects with a TypeError if the worklet module has not been added with SharedStorageWorklet.addModule().

[!NOTE] In the case of WindowSharedStorage, if the append() operation doesn’t successfully write to the database for a reason other than shared storage not being available, no error is thrown — the operation still fulfills with undefined.

Examples

window.sharedStorage
  .append("integer-list", ",9")
  .then(() => console.log("Value appended to integer list"));

Specifications

Browser compatibility

See also

• Shared Storage API