IDBIndex: getAll() method
  The getAll() method of the IDBIndex
  interface retrieves all objects that are inside the index.
  There is a performance cost associated with looking at the value property
  of a cursor, because the object is created lazily. To use a feature
  like getAll(), the browser has to create all the objects at once. If you
  are just interested in looking at each of the keys, for instance, it is more efficient
  to use a cursor. If you are trying to get an
  array of all the objects in an object store, though, you should
  use getAll().
Syntax
getAll()
getAll(query)
getAll(query, count)
Parameters
queryOptional- 
    
A key or an
IDBKeyRangeidentifying the records to retrieve. If this value is null or missing, the browser will use an unbound key range. countOptional- 
    
The number of records to return. If this value exceeds the number of records in the query, the browser will only retrieve the queried records. If it is lower than
0or greater than2^32 - 1aTypeErrorexception will be thrown. 
Return value
An IDBRequest object on which subsequent events related to this operation are fired.
If the operation is successful, the value of the request's result property is an Array of the values of all records matching the given query, up to the value of count, if count was supplied.
Exceptions
This method may raise a DOMException of the following types:
TransactionInactiveErrorDOMException- 
    
Thrown if this
IDBIndex's transaction is inactive. InvalidStateErrorDOMException- 
    
Thrown if the
IDBIndexhas been deleted or removed. 
  A TypeError exception is thrown if the count parameter is
  not between 0 and 2^32 - 1 included.
Examples
const myIndex = objectStore.index("index");
const getAllRequest = myIndex.getAll();
getAllRequest.onsuccess = () => {
  console.log(getAllRequest.result);
};
Specifications
| Specification | 
|---|
| Indexed Database API 3.0  # ref-for-dom-idbindex-getall①  | 
Browser compatibility
BCD tables only load in the browser
See also
- Using IndexedDB
 - Starting transactions: 
IDBDatabase - Using transactions: 
IDBTransaction - Setting a range of keys: 
IDBKeyRange - Retrieving and making changes to your data: 
IDBObjectStore - Using cursors: 
IDBCursor - Reference example: To-do Notifications (View the example live).