LocalStorage

A class that provides a set of methods for interacting with the browser's local storage.

Installation & setup

NPM

You can install the package via npm:

npm install @bjnstnkvc/local-storage

and then import it into your project

import { LocalStorage } from '@bjnstnkvc/local-storage';

CDN

You can install the package via jsDelivr CDN:

<script src="https://cdn.jsdelivr.net/npm/@bjnstnkvc/local-storage/lib/main.min.js"></script>

Usage

set

Set the value for a given key in the Local Storage.

Parameters

• key - String containing the name of the key.
• value - The value to be stored.
• ttl (optional) - Time to live in seconds for the key. Defaults to null (no expiration) or equal to LocalStorage.ttl value.

Example

LocalStorage.set('key', 'value', 60); 

get

Retrieve the value associated with the given key from the Local Storage.

Parameters

• key - String containing the name of the key.
• fallback (optional) - The fallback value in case the key does not exist. Defaults to null.

Example

LocalStorage.get('key', 'default');

You can also pass a closure as the default value. If the specified item is not found in the Local Storage, the closure will be executed and its result returned. This allows you to lazily load default values from other sources:

LocalStorage.get('key', () => 'default');

Note: When you attempt to retrieve a value using the get method, it checks if the item has expired based on its TTL (Time-To-Live). If the item has indeed expired, it is automatically removed from the LocalStorage, ensuring that your application only works with valid, up-to-date data.

remember

Retrieve the value associated with the given key, or execute the given callback and store the result in the Local Storage.

Parameters

• key - String containing the name of the key.
• fallback - Function you want to execute.
• ttl (optional) - Time to live in seconds for the key. Defaults to null (no expiration) or equal to LocalStorage.ttl value.

Example

LocalStorage.remember('key', () => 'default', 60);

all

Retrieve an array containing all keys and their associated values stored in the Local Storage.

Example

LocalStorage.all();

Note: The all method returns an array of objects with key and value properties (e.g. [{ key: 'key', value: 'value' }])

remove

Remove the key and its associated value from the Local Storage.

Parameters

• key - String containing the name of the key to be deleted.

Example

LocalStorage.remove('key');

clear

Clear all keys and their associated values from the Local Storage.

Example

LocalStorage.clear();

has

Check if a key exists in the Local Storage.

Parameters

• key - String containing the name of the key to be checked.

Example

LocalStorage.has('key');

missing

Check if a key does not exist in the Local Storage.

Parameters

• key - String containing the name of the key to be checked.

Example

LocalStorage.missing('key');

hasAny

Check if any of the provided keys exist in the Local Storage.

Parameters

• keys - String or an array of strings containing the names of the keys to be checked.

Example

LocalStorage.hasAny(['key1', 'key2']);

isEmpty

Check if the Local Storage is empty.

Example

LocalStorage.isEmpty();

isNotEmpty

Check if the Local Storage is not empty.

Example

LocalStorage.isNotEmpty();

keys

Retrieve an array containing all keys stored in the Local Storage.

Example

LocalStorage.keys();

count

Retrieve the total number of items stored in the Local Storage.

Example

LocalStorage.count();

touch

Update the expiration time of a key in the Local Storage.

Parameters

• key - String containing the name of the key.
• ttl (optional) - Time to live in seconds for the key. Defaults to null (no expiration) or equal to LocalStorage.ttl value.

Example

LocalStorage.touch('key', 60);

expiry

Retrieve the expiration date for a given key.

Parameters

• key - String containing the name of the key you want to check against

Example

LocalStorage.expiry('key');

You can also pass a boolean as the second parameter to return the expiration date as a Date object:

LocalStorage.expiry('key', true);

dump

Print the value associated with a key to the console.

Parameters

• key - String containing the name of the key.

Example

LocalStorage.dump('key');

fake

Replace the Local Storage instance with a fake implementation. This is particularly useful for testing purposes where you want to avoid interacting with the actual browser's Local Storage.

Example

LocalStorage.fake();

restore

Restore the original Local Storage instance. This is typically used after fake() to return to using the real browser's Local Storage.

Example

LocalStorage.restore();

isFake

Check if a fake Local Storage instance is currently being used.

Example

if (LocalStorage.isFake()) {
    // ...
}

ttl

Define a global Time-To-Live (TTL) in seconds for all items saved using the LocalStorage.set or LocalStorage.touch method, without specifying a TTL for each item. This can be particularly useful for applications needing a consistent expiry policy for most stored data.

Example

LocalStorage.ttl(7200);

If a default TTL has been set using LocalStorage.ttl, it will be applied to all items set without a specified TTL.

Events

In case you would like to execute a callback on Local Storage operation, you may listen for various events dispatched by the Local Storage.

| Type | Event | |-----------------|-----------------| | retrieving | RetrievingKey | | hit | KeyHit | | missed | KeyMissed | | writing | WritingKey | | written | KeyWritten | | write-failed | KeyWriteFailed | | forgot | KeyForgotten | | forgot-failed | KeyForgotFailed | | flushing | StorageFlushing | | flushed | StorageFlushed |

listen

Register an event listener for one or more storage events.

Parameters

• events - String or an object of strings containing the type and a callback function.
• callback - Function to be executed when the event is dispatched in case an event is passed as a string.

Example

LocalStorage.listen('retrieving', (event) => {
    console.log(event);
});

In case you would like to register multiple events, you can pass an object containing the type and a callback function:

LocalStorage.listen({
    'retrieving': (event) => {
        // ...
    },
    'hit': (event) => {
        // ...
    },
    'missed': (event) => {
        // ...
    },
    'writing': (event) => {
        // ...
    },
    'written': (event) => {
        // ...
    },
    'write-failed': (event) => {
        // ...
    },
    'forgot': (event) => {
        // ...
    },
    'forgot-failed': (event) => {
        // ...
    },
    'flushing': (event) => {
        // ...
    },
    'flushed': (event) => {
        // ...
    },
});

Conveniently, you can also use the following methods to register event listeners for a specific event:

onRetrieving

Triggered when a key is about to be retrieved from storage.

LocalStorage.onRetrieving((event) => {
  // ...
});

onHit

Triggered when a requested key is found in the storage.

LocalStorage.onHit((event) => {
  // ...
});

onMissed

Triggered when a requested key is not found in the storage.

LocalStorage.onMissed((event) => {
  // ...
});

onWriting

Triggered when a key is about to be written to storage.

LocalStorage.onWriting((event) => {
  // ...
});

onWritten

Triggered after a key has been successfully written to storage.

LocalStorage.onWritten((event) => {
  // ...
});

onWriteFailed

Triggered when writing a key to storage fails.

LocalStorage.onWriteFailed((event) => {
  // ...
});

onForgot

Triggered when a key is successfully removed from storage.

LocalStorage.onForgot((event) => {
  // ...
});

onForgotFailed

Triggered when removing a key from storage fails.

LocalStorage.onForgotFailed((event) => {
  // ...
});

onFlushing

Triggered when the storage is about to be cleared.

LocalStorage.onFlushing((event) => {
  // ...
});

onFlushed

Triggered after the storage has been successfully cleared.

LocalStorage.onFlushed((event) => {
    // ...
});