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SharedStorage: append() method

Limited availability

This feature is not Baseline because it does not work in some of the most widely-used browsers.

Experimental: This is an experimental technology
Check the Browser compatibility table carefully before using this in production.

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

Specification
Shared Storage API> # dom-sharedstorage-append>

Browser compatibility

	Desktop					Mobile
	Chrome	Edge	Firefox	Opera	Safari	Chrome Android	Firefox for Android	Opera Android	Safari on IOS	Samsung Internet	WebView Android	WebView on iOS
`append`	126	126	No	112	No	126	No	83	No	28.0	126	No