wp-calypso/client/lib/browser-storage/README.md

browser-storage

This implements a simple promise-based key-value store using IndexedDB, if available, and falling back to localStorage otherwise.

Usage

import { getStoredItem, setStoredItem, clearStorage } from 'calypso/lib/browser-storage';

setStoredItem( 'my-stored-key', { complex: value } ).then( () => doSomething() );
getStoredItem( 'my-stored-key' ).then( ( val ) => doSomethingWithVal( val ) );
clearStorage().then( () => console.log( 'Storage cleared' ) );

undefined is returned as the value for missing keys.

Bypassing persistent storage

In some cases, such as support sessions, it's useful to bypass persistent storage altogether, using a volatile memory store instead. The bypassPersistentStorage method exists to toggle that behavior on and off.

import { setStoredItem, bypassPersistentStorage } from 'calypso/lib/browser-storage';

async function demo() {
    // Use persistent storage.
    await setStoredItem( 'my-stored-key', 'some value' );

    // Use memory storage.
    bypassPersistentStorage( true );
    await setStoredItem( 'my-stored-key', 'another value' );

    // Use persistent storage again.
    bypassPersistentStorage( false );
    console.log( await getStoredItem( 'my-stored-key' ) ); // 'some value'
}

bypassPersistentStorage clears the memory store every time it's called with a truthy value.