Supports promises, iteration and default values. Written in TypeScript. Uses the storage-facade library which is provides a single storage API that abstracts over the actual storage implementation.
npm install storage-facade@4 storage-facade-indexeddb@1
The following code
import { createStorage } from 'storage-facade';
import { IndexedDBInterface } from 'storage-facade-indexeddb';
(async () => {
const storage1 = createStorage({
use: new IndexedDBInterface(),
name: 'storageOne', // ObjectStore name
dbName: 'DB_One', // DB name
});
const storage2 = createStorage({
use: new IndexedDBInterface(),
name: 'storageTwo', // ObjectStore name
dbName: 'DB_Two', // DB name
});
// DB_One
storage1.pen = { data: [40, 42] };
await storage1.pen; // Successfully written
storage1.pineApple = 10;
await storage1.pineApple;
// DB_Two
storage2.deletedVar = 'This value will be deleted';
await storage2.deletedVar;
console.log(
'In IndexedDB:',
await storage2.deletedVar
); // 'In IndexedDB: This value will be deleted'
storage2.apple = [1, 2, 3];
await storage2.apple;
// delete key
delete storage2.deletedVar;
await storage2.deletedVar; // Successfully deleted
storage2.pen = 'Uh!';
await storage2.pen;
})();
will create such keys in IndexedDB:
As you can see, each value is wrapped in an object
{ index: ..., key: ..., value: ... }
, and after removing one of the keys,
the index
fields of the objects have the correct value.
This is necessary for iteration over storage keys to work in storage-facade
.
There are similar libraries for other storages: localStorage, sessionStorage, Map.
.clear()
- removes all key-value pairs from the storage.getEntries()
returns an array of promises to iterate.deleteStorage()
- delete storage.size()
- returns the number of key-value pairs.key(index: number)
- returns the name of the key by its index
The key
and size
methods can be used to create custom iterators.
The default values are used if the value in the storage is undefined
.
Default values are not stored in the storage, but in the instance.
Therefore, all these methods are synchronous (no need to use the await
keyword):
.addDefault(obj)
- adds keys and values from the passed object to the list of default values.setDefault(obj)
- replaces the list of default values with the given object.getDefault()
- returns an object containing default values.clearDefault()
- replaces a list of default values with an empty object
import { createStorage } from 'storage-facade';
import { IndexedDBInterface } from 'storage-facade-indexeddb';
(async () => {
const storage = createStorage({
use: new IndexedDBInterface(),
name: 'cfg', // IDBObjectStore name, optional, default: 'storage'
// Limitation: the `dbName` cannot be the same for two storages.
// In other words, each database can have only one objectStore
dbName: 'App' // IDBDatabase name, optional, default: equal to `name`
});
// If an error occurs at the initialization stage,
// it will be thrown at the first attempt
// to access the storage (read, write, all methods except
// 'addDefault, setDefault, getDefault, clearDefault')
// Write
storage.value = { data: [40, 42] };
// After the assignment, wait for the write operation to complete
await storage.value; // Successfully written
// Read value
console.log(await storage.value); // { data: [40, 42] }
// When writing, accesses to first-level keys are intercepted only,
// so if you need to make changes inside the object,
// you need to make changes and then assign it to the first level key.
// Get object
const updatedValue = (await storage.value) as Record<string, unknown>;
// Make changes
updatedValue.data = [10, 45];
// Update storage
storage.value = updatedValue;
await storage.value; // Successfully written
// Read value
console.log(
((await storage.value) as Record<string, unknown>).data
); // [10, 45]
// OR
const value = (await storage.value) as Record<string, unknown>;
console.log(value.data); // [10, 45]
// Delete value
delete storage.value;
await storage.value; // Successfully deleted
console.log(await storage.value); // undefined
storage.value = 30;
await storage.value;
console.log(await storage.value); // 30
// Clear storage
await storage.clear();
console.log(await storage.value); // undefined
// Delete storage
await storage.deleteStorage();
// An error will be thrown when trying to access
// console.log(await storage.value); // Err: 'This Storage was deleted!'
})();
import { createStorage } from 'storage-facade';
import { IndexedDBInterface } from 'storage-facade-indexeddb';
(async () => {
const storage = createStorage({
use: new IndexedDBInterface(),
});
storage.value = 4;
await storage.value;
storage.other = 5;
await storage.other;
const promisesArray = await storage.getEntries();
const array = promisesArray.map(async (kv) => {
const [key, value] = await kv;
// ... add code here ...
return [key, value];
});
console.log(await Promise.all(array));
/*
[
['value', 4],
['other', 5],
]
*/
})();
import { createStorage } from 'storage-facade';
import { IndexedDBInterface } from 'storage-facade-indexeddb';
(async () => {
const storage = createStorage({
use: new IndexedDBInterface(),
});
console.log(await storage.value) // undefined
storage.addDefault({ value: 9, other: 3 });
storage.addDefault({ value: 1, value2: 2 });
// Since `storage.value = undefined` the default value is used
console.log(await storage.value); // 1
console.log(await storage.value2); // 2
console.log(await storage.other); // 3
storage.value = 42;
await storage.value;
// When we set a value other than `undefined`,
// the default value is no longer used
console.log(await storage.value); // 42
storage.value = undefined;
await storage.value;
console.log(await storage.value); // 1
storage.value = null;
await storage.value;
console.log(await storage.value); // null
delete storage.value;
await storage.value;
console.log(await storage.value); // 1
// getDefault
console.log(storage.getDefault()); // { value: 1, value2: 2, other: 3 }
// Replace 'default'
storage.setDefault({ value: 30 });
console.log(await storage.value); // 30
console.log(await storage.value2); // undefined
// clearDefault
storage.clearDefault();
console.log(await storage.value); // undefined
console.log(await storage.value2); // undefined
})();
The dbName
cannot be the same for two storages.
In other words, each database can have only one objectStore.
import { createStorage } from 'storage-facade';
import { IndexedDBInterface } from 'storage-facade-indexeddb';
(async () => {
const storage1 = createStorage({
use: new IndexedDBInterface(),
name: 'storageOne',
dbName: 'DB_One',
// ^^^^^^
});
const storage2 = createStorage({
use: new IndexedDBInterface(),
name: 'storageTwo',
dbName: 'DB_One',
// ^^^^^^
});
// DB_One
storage1.pen = 10;
await storage1.pen;
// DB_Two
storage2.apple = 20;
await storage2.apple;
// Error: DOMException: IDBDatabase.transaction: 'storageTwo' is not a
// known object store name
})();
When writing, accesses to first-level keys (like storage.a =
,
but not storage.a[0] =
or storage.a.b =
) are intercepted only,
so if you need to make changes inside the object, you need to make changes
and then assign it to the first level key.
Assigning keys of the second or more levels will not give any effect.
// Read
console.log(
((await storage.value) as Record<string, unknown>).data
); // Ok
// Write
// Don't do that
storage.value.data = 42; // no effect
Instead, use the following approach:
// Read
console.log(
((await storage.value) as Record<string, unknown>).data
); // Ok
// Write
// Get object
const updatedValue = (await storage.value) as Record<string, unknown>;
// Make changes
updatedValue.data = 42;
// Update storage
storage.value = updatedValue;
await storage.value // ΠΠΊ
There is a list of key names that cannot be used because they are the same
as built-in method names: [clear
, deleteStorage
, size
, key
,
getEntries
, entries
, addDefault
, setDefault
, getDefault
, clearDefault
].
Use the keyIsNotBanned
function to check the key if needed.
import { createStorage, keyIsNotBanned } from 'storage-facade';
import { IndexedDBInterface } from 'storage-facade-indexeddb';
const storage = createStorage({
use: new IndexedDBInterface(),
asyncMode: false,
});
try {
const myNewKey = 'newKey';
if (keyIsNotBanned(myNewKey)) {
storage[myNewKey] = 42;
}
} catch (e) {
console.error((e as Error).message);
}
Only values of type string
can be used as keys.
Values for [addDefault
, setDefault
] methods
should be of any structured-cloneable type (MDN).