@varasto/storage v5.0.0
@varasto/storage
Type definitions for Varasto JSON key-value store.
Installation
$ npm install --save @varasto/storageUsage
This package provides abstract base class for Varasto storage implementations as well as error classes to indicate that an item identifier (either namespace or key) does not pass the slug validation or that an item being updated does not exist.
Usually you don't need to use or install this package directly, but use an storage implementation package instead. Below is an list of storage implementations for different use cases.
| Name | Description |
|---|---|
| cache-storage | Acts as an cache for another storage. |
| fs-storage | Stores data persistently to hard disk. |
| memory-storage | Stores data to memory. |
| multi-storage | Stores data to multiple other storages. |
| postgres-storage | Stores data to PostgreSQL database. |
| remote-storage | Stores data to remote server. |
| redis-storage | Stores data to Redis. |
| single-file-storage | Stores data to a single file. |
| sqlite-storage | Stores data to SQLite database. |
| validator-storage | Acts as an validator for another storage. |
| web-storage | Stores data to browser storage. |
Storing items
set<T extends JsonObject>(
namespace: string,
key: string,
value: T
): Promise<void>Attempts to store an item identified by namespace and key. Returned
promise will fail if an I/O error occurs while storing the item.
Retrieving items
get<T extends JsonObject>(
namespace: string,
key: string
): Promise<T | undefined>Attempts to retrieve an item identified by namespace and key. Returned
promise will either resolve into the value, or undefined if item with the
given identifier does not exist. The promise will fail if an I/O error
occurs while retrieving the item.
Removing items
delete(
namespace: string,
key: string
): Promise<boolean>Attempts to remove an item identified by namespace and key. Returned
promise will resolve into a boolean value which tells whether an value with
the given identifier existed or not. The promise will fail if an I/O error
occurs while removing the item.
Searching for entries
find<T extends JsonObject>(
namespace: string,
callback: (value: T, key: string) => boolean
): Promise<[string, T | undefined]>Returns the first entry from specified namespace to which given callback
function returns true for, or undefined if the callback function does not
return true for any entry in the namespace.
The promise will fail if an I/O error occurs, or if given namespace is not a valid slug.
Updating already existing item
update<T extends JsonObject>(
namespace: string,
key: string,
value: Partial<T>
): Promise<T>Attempts to update an already existing item identified by namespace and key
by shallowly merging with the given new data. Returned promise will resolve
into the new value, or will fail if no such item exists.
Testing whether an item exists or not
has(
namespace: string,
key: string
): Promise<boolean>Returns true if an item identified by namespace and key exists in the
storage, or false if it doesn't. The promise will fail if an I/O error
occurs while testing whether item exists or not.
Listing keys stored in a namespace
keys(
namespace: string
): AsyncGenerator<string>Lists keys of all items stored under an namespace. The promise will fail if an I/O error occurs while listing the keys.
Listing values stored in a namespace
values<T extends JsonObject>(
namespace: string
): AsyncGenerator<T>Lists all items stored under an namespace. The promise will fail if an I/O error occurs.
Listing entries stored in a namespace
entries<T extends JsonObject>(
namespace: string
): AsyncGenerator<[string, T]>Lists all items stored under an namespace, with the keys they are identified by. The promise will fail if an I/O error occurs.
Filtering entries stored in a namespace
filter<T extends JsonObject>(
namespace: string,
callback: (value: T, key: string) => boolean
): AsyncGenerator<[string, T]>Goes through all entries from the given namespace, returning ones for which
the given callback functions returns true for.
The promise will fail if an I/O error occurs, or if given namespace is not a valid slug.
Map operation
map<T extends JsonObject, U extends JsonObject>(
namespace: string,
callback: (value: T, key: string) => U
): AsyncGenerator<[string, U]>Goes through all entries from the given namespace, passing them to the given callback function and returning whatever the callback function returned.
The promise will fail if an I/O error occurs, or if given namespace is not a valid slug.