Superutils

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Class: Store<Key, Value, CacheDisabled, This> ​

Defined in: store/src/Store.ts:199

A generic, reactive data storage class that provides a Map-like interface with advanced features such as search, filtering, and sorting. Supports both in-memory caching and persistent storage (LocalStorage in browsers, JSON files in NodeJS via node-localstorage NPM module).

Notes: ​

  • Performance: Store is optimized for small to medium datasets.
    • For datasets > 1MB, consider increasing the delay option to reduce write frequency.
    • It is NOT recommended for datasets larger than 3MB due to synchronous serialization costs.
    • For one-off operations or standalone scripts, data size is constrained only by available system memory and processing power.
  • RxJS Integration: Built on RxJS for reactive data handling, though no prior RxJS knowledge is required.
  • Storage Behavior:
    • If name is omitted, the instance operates in-memory only and data is not persisted to storage.
    • If cacheDisabled is true, data is not kept in memory; every read/write operation accesses the underlying storage directly.

See ​

forceUpdateCache$ for cache invalidation across instances.

Examples ​

Browser Usage 1: use like a map ​

javascript
import { Store } from '@superutils/store'

const userStore = new Store('users')
userStore.set(1, { name: 'Alice', age: 30 })
const user = userStore.get(1)
console.log(user) // prints: {name: 'Alice', age: 30}

Browser Usage 2: ​

javascript
import { Store } from '@superutils/store'
import fetch from '@superutils/fetch'

const { products } = await fetch.get('[DUMMYJSON-DOT-COM]/products')
const storage = new Store('products', {
  initialValue: new Map(products.map(p => [p.id, p])) // convert to Map
})

// print product with id `1`
console.log(storage.get(1))

// search for items
const searchResult = storage.search({
  query: { availabilityStatus: 'low' }
})
console.log(searchResult)

NodeJS Usage ​

javascript
import { Store } from '@superutils/store'
import fetch from '@superutils/fetch'
import { LocalStorage } from 'node-localstorage'

// Add localStorage alternative for NodeJS that reads and writes to JSON files.
// This is not necessary for browsers.
globalThis.localStorage = new LocalStorage('./data', 1e7)

const storage = new Store('products')
const { products } = await fetch.get('[DUMMYJSON-DOT-COM]/products')
// save all items to storage
storage.setAll(
  new Map(products.map(p => [p.id, p])), // convert to Map
)

// print product with id `1`
console.log(storage.get(1))

// search for items
const searchResult = storage.search({
  query: { availabilityStatus: 'low' }
})
console.log(searchResult)

Advanced: onChange and RxJS subject ​

Internally, Store uses RxJS subject which is exposed as subject$ property. You can use this to subscribe to changes and do additional operations such as logging or sanitization etc.

Alternatively, you can also set the onChange callback which is triggered whenever the subject changes and does not require maintaining a subscription or knowledge of RxJS subject.

javascript
import { Store } from '@superutils/store'

const storage = new Store('my-data')
const sub = storage.subject$.subscribe(data => {
  // Write to the database whenever data changes
  console.log('Saving to database...', data)
})
// unsubscribe from subject
setTimeout(()=> sub.unsubscribe(), 1000)

// add an entry to storage
storage.set('bob', { age: 99, id: 'bob', name: 'Bob' })

Type Parameters ​

Key ​

Key

The type of keys stored in the map.

Value ​

Value

The type of values stored in the map.

CacheDisabled ​

CacheDisabled extends boolean = false

A literal boolean type indicating whether in-memory caching is disabled.

This ​

This extends IStore<Key, Value, CacheDisabled> = IStore<Key, Value, CacheDisabled>

A self-referential interface type extending IStore used for accurate method signature inference and type-safe property access. This allows method implementations to reference their return types and other method signatures through the interface definition.

Implements ​

  • IStore<Key, Value, CacheDisabled>

Constructors ​

Constructor ​

new Store<Key, Value, CacheDisabled, This>(name?, options?): Store<Key, Value, CacheDisabled, This>

Defined in: store/src/Store.ts:264

Parameters ​

name? ​

This["name"]

options? ​

Store_Options<Key, Value, CacheDisabled>

Returns ​

Store<Key, Value, CacheDisabled, This>

Properties ​

cacheDisabled ​

readonly cacheDisabled: This["cacheDisabled"]

Defined in: store/src/Store.ts:225

Disable in-memory cache and only directly read/write from storage (local storage or JSON fle)

Implementation of ​

IStore.cacheDisabled

clear ​

clear: This["clear"]

Defined in: store/src/Store.ts:323

Clear all items

Implementation of ​

IStore.clear

delay ​

readonly delay: This["delay"]

Defined in: store/src/Store.ts:227

Debounce/throttle delay duration in milliseconds for writing to storage when caching is enabled.

Increasing this value can improve performance when dealing with large datasets or frequent updates by reducing the number of write operations.

Default: 300

Implementation of ​

IStore.delay

delayOptions? ​

readonly optional delayOptions?: This["delayOptions"]

Defined in: store/src/Store.ts:229

Debounce and throttle related options

Implementation of ​

IStore.delayOptions

delete ​

delete: This["delete"]

Defined in: store/src/Store.ts:330

Delete one or more items by their respective keys

Implementation of ​

IStore.delete

entries ​

entries: This["entries"]

Defined in: store/src/Store.ts:361

Get entries (2D Array)

Implementation of ​

IStore.entries

filter ​

filter: This["filter"]

Defined in: store/src/Store.ts:343

Filter items by predicate

Implementation of ​

IStore.filter

find ​

find: This["find"]

Defined in: store/src/Store.ts:345

Find an item by predicate or search criteria

Implementation of ​

IStore.find

get ​

get: This["get"]

Defined in: store/src/Store.ts:363

Get item by key

Implementation of ​

IStore.get

getAll ​

getAll: This["getAll"]

Defined in: store/src/Store.ts:365

Get all items

Param ​

forceUpdate

(optional) if true and cache is enabled, reads & updates data directly from storage

Default: false

Param ​

silent

(optional) Whether to throw error on failure.

Default: true

Returns ​

data map

Implementation of ​

IStore.getAll

has ​

has: This["has"]

Defined in: store/src/Store.ts:421

Check if key exists

Implementation of ​

IStore.has

init ​

init: This["init"]

Defined in: store/src/Store.ts:423

Initializes storage and sets up internal subscriptions.

Manual invocation is not typically necessary, as initialization occurs automatically in one of the following scenarios:

  • During construction, if an initialValue with at least one entry is provided.
  • On the first attempt to read or write data.

Param ​

initialValue

(optional) An optional map to initialize the storage with if it's currently empty.

Param ​

silent

(optional) Whether to throw error on failure.

Default: true

Returns ​

true if initialization was successful, or false if the storage was already initialized.

Implementation of ​

IStore.init

initialized ​

readonly initialized: This["initialized"] = false

Defined in: store/src/Store.ts:231

Indicates wherether storage has been initialized (init() function invoked).

Implementation of ​

IStore.initialized

keys ​

keys: This["keys"]

Defined in: store/src/Store.ts:487

Get all keys

Implementation of ​

IStore.keys

map ​

map: This["map"]

Defined in: store/src/Store.ts:489

Map each item on the data to an Array

Implementation of ​

IStore.map

name ​

readonly name: This["name"]

Defined in: store/src/Store.ts:233

Storage name. Filename (NodeJS) or property name (browser LocalStorage). If empty string or undefined, data will not be saved to storage and will only work in-memory.

Default: null

Implementation of ​

IStore.name

onChange? ​

optional onChange?: This["onChange"]

Defined in: store/src/Store.ts:235

A callback function executed whenever a data change occurs within the storage.

This hook allows for reactive side-effects. If the callback throws an error or returns a rejected Promise, the exception is caught gracefully and redirected to the onError callback with the type Store_OnErrorType.onChange.

Note: Execution of this callback is managed by internal subscriptions and will stop firing once unsubscribe is called.

Implementation of ​

IStore.onChange

onError? ​

optional onError?: This["onError"]

Defined in: store/src/Store.ts:237

A global error handler invoked whenever an internal operation fails.

It captures failures in the following areas:

  • Data parsing and serialization (JSON or custom logic).
  • Storage access (e.g., localStorage quota or permission errors).
  • Execution of user-provided callbacks like onChange.

Note: If this handler itself throws an error, the exception is ignored gracefully to prevent application crashes during storage cycles.

Implementation of ​

IStore.onError

parse? ​

optional parse?: This["parse"]

Defined in: store/src/Store.ts:239

A callback to customize the deserialization of data read from storage.

This allows you to transform the raw string from the underlying storage back into a Map<Key, Value>. It serves as the functional inverse of stringify.

Fallback Behavior:

  • If this function is not defined, or returns undefined or a non-map value, the system falls back to internal JSON.parse logic.
  • If the function throws an error, it will use and empty map.

Error Triggers:

Implementation of ​

IStore.parse

read ​

read: This["read"]

Defined in: store/src/Store.ts:494

Reads and parses data directly from the persistent storage medium.

This operation is synchronous and does not trigger reactive updates via subject$. It is useful for debugging custom parse logic or manual data retrieval.

If instance.parse function is provided and invokation fails, an empty Map will be returned.

Param ​

dataStr

(optional) A raw string to parse. If omitted, the method fetches the current value associated with the instance name from the underlying storage.

Default: null

Param ​

silent

(optional) Whether to throw error on failure.

Default: false

Implementation of ​

IStore.read

search: This["search"]

Defined in: store/src/Store.ts:546

Search through the stored data (Map<Key, Value>). It supports both a global search (using a string or RegExp) across all properties of an item, and a detailed, field-specific search using a query object.

Param ​

options

The search criteria. See SearchOptions for available properties.

Returns ​

A Map or an Array containing the matched items, based on the asMap option.

Example ​

Search for users in a specific city ​

javascript
import { Store } from '@superutils/store'

const storage = new Store('users', {
  initialValue: new Map([
    [1, { name: 'John Doe', city: 'New York' }],
    [2, { name: 'Jane Doe', city: 'London' }],
    [3, { name: 'Peter Jones', city: 'New York' }],
  ])
})

const nyUsers = storage.search({ query: { city: 'New York' } })
console.log(nyUsers.size) // 2

Implementation of ​

IStore.search

set ​

set: This["set"]

Defined in: store/src/Store.ts:548

Set item by key

Param ​

key

Param ​

value

value or function

Param ​

silent

(optional) Whether to throw error on failure.

Default: true

Example ​

javascript
import { Store } from '@superutils/store'

const store = new Store<string, number>()
store.set('count', 1)
store.set('count', (prevCount = 0) => prevCount + 1)

Implementation of ​

IStore.set

setAll ​

setAll: This["setAll"]

Defined in: store/src/Store.ts:560

Set multiple entries at once and/or replace the storage entries

Param ​

data

(optional) Data to add. Default: new Map()

Param ​

replace

(optional) Whether to merge with or replace current data.

  • true: replace all entries with data
  • false: merge with current data (existing entries with matching keys will be overwritten)

Default: false

Param ​

silent

(optional) Whether to throw error on failure.

Default: true

Returns ​

store instance

Implementation of ​

IStore.setAll

sort ​

sort: This["sort"]

Defined in: store/src/Store.ts:581

Sort items in the storage.

Param ​

nameOrComparator

Criteria to sort by. Accepts one of the following:

  • function: A comparator function to sort the data.
  • string: A property name of the value object to sort by.
  • true: Sorts the map by its keys.

Param ​

options

(optional) Sorting options.

Param ​

options.save

(optional) Whether to save the sorted data back to storage (localStorage/file).

Returns ​

The sorted Map.

Implementation of ​

IStore.sort

spaces? ​

optional spaces?: This["spaces"]

Defined in: store/src/Store.ts:247

Number of spaces to use when stringifying. Default: undefined

Implementation of ​

IStore.spaces

storage? ​

readonly optional storage?: This["storage"]

Defined in: store/src/Store.ts:249

LocalStorage or equivalent storage instance to be used as the underlying storage and to read & write from.

Notes:

  • Ignored when name is falsy (in-memory only mode)
  • For NodeJS or equivalent, an instance of LocalStorage from "node-localstoarge" NPM module can be used.
  • A custom storage that implements StorageCompact interface can also be used both in browser and NodeJS.

Fallback behavior:

  • undefined: will attempt to use globalThis.localStorage, if available
  • null, will defer storage check until initialization on first read/write or when init() invoked manually.
    • If storage is undefined or null will attempt to assign globalTihs.localStorage again
    • If storage is still falsy, will throw an error.

Default:

  • browser: localStorage
  • node: undefined (in-memory mode)

Implementation of ​

IStore.storage

stringify? ​

optional stringify?: This["stringify"]

Defined in: store/src/Store.ts:251

A callback function to customize the serialization of data before it is written to storage.

This allows you to transform the data Map<Key, Value> into a string format suitable for the underlying storage (e.g., JSON). It serves as the functional inverse of parse.

Use this to sanitize data, remove circular references, or optimize the storage size by only persisting necessary fields.

Fallback Behavior:

  • If this function is not defined, or returns undefined or a non-string value, the system falls back to internal JSON.stringify logic.
  • If the function throws an error, it will use and empty string.

Error Triggers:

Param ​

data

a map of all values stored in this storage

Returns ​

string or undefined

Example ​

Sanitize data before saving ​

javascript
import { Store } from '@superutils/store'

const stringify = (data) => {
  // Convert Map to an array of entries, removing sensitive fields
  const entries = Array.from(data).map(([id, user]) => { // eslint-disable-line @typescript-eslint/no-unused-vars
    const { password, ...publicData } = user
    return [id, publicData]
  })
  return JSON.stringify(entries)
}
const storage = new Store('users', { stringify })

Implementation of ​

IStore.stringify

subject$ ​

readonly subject$: This["subject$"]

Defined in: store/src/Store.ts:253

The underlying RxJS subject that serves as the primary reactive interface for observing data modifications.

Its implementation type is determined by the caching strategy:

  • BehaviorSubject: Used when caching is enabled. It maintains the current state and emits it immediately to new subscribers.
  • Subject: Used when caching is disabled. It acts as a pure event pipe, emitting updates only at the moment they occur without retaining an in-memory copy.

Implementation of ​

IStore.subject$

toJSON ​

toJSON: This["toJSON"]

Defined in: store/src/Store.ts:592

Convert list of items (Map) to JSON string of 2D Array

Implementation of ​

IStore.toJSON

toObject ​

toObject: This["toObject"]

Defined in: store/src/Store.ts:622

Convert list of items into an object

Implementation of ​

IStore.toObject

toString ​

toString: This["toString"]

Defined in: store/src/Store.ts:632

Convert list of items (Map) to JSON string of 2D Array

Implementation of ​

IStore.toString

type ​

type: This["type"]

Defined in: store/src/Store.ts:260

Specifies how the store's data is represented when stored in and parsed from the underlying persistent storage.

  • 'map': Data is serialized as a 2D array (map entries).
  • 'object': Data is serialized as a plain object, with keys and values converted using IStore.toObject.

Default: 'map'

Implementation of ​

IStore.type

unsubscribe ​

unsubscribe: This["unsubscribe"]

Defined in: store/src/Store.ts:654

Unsubscribe from all internal subscriptions.

This will result in:

  • Automatic writing to storage being disabled (manual writes via instance.write() will still work).
  • The onChange callback no longer being triggered.
  • The instance stopping listening to force update cache triggers.

Implementation of ​

IStore.unsubscribe

validate? ​

optional validate?: This["validate"]

Defined in: store/src/Store.ts:262

A configuration object containing optional validation hooks for specific store operations.

This structure allows for granular control over write operations, enabling you to define custom logic to intercept and prevent invalid state updates.

Behavior:

  • Invoked immediately before the store's internal state is updated.
  • If validator throws error, the operation is aborted and the error is propagated to the caller.
  • If validator returns false, the operation is aborted silently.
  • The write validator is invoked during every persistence cycle, serving as a final check after operation-specific hooks (e.g., set or delete).
  • For reference-type values (e.g., Objects, Maps, Arrays), validators can be used to mutate the data (e.g., for normalization) before it is committed.
  • thisArg: all validators are bound to the store instance.

For a list of actions that can be validated, see IStore_ValidatorParams.

Example ​

javascript
import { createObjectStore } from '@superutils/store'

const settingsStore = createObjectStore({
  name: 'app-settings',
  initialValue: {
    theme: 'light',
    version: '1.0.0',
  },
  validate: {
    set([key, value]) {
      console.log(this.size) // "this" refers to the store instance
      if (key !== 'theme' || ['light', 'dark', 'system'].includes(value)) return

      // throw error to abort operation
      throw new Error(`Invalid theme: ${value}`)
    },
    delete: ([keys]) => !keys.includes('version'),
  },
})

settingsStore.set('theme', 'system')
console.log(settingsStore.get('theme')) // 'system'

try {
  settingsStore.set('theme', 'invalid') // throws error
} catch (err) {
  console.error(err.message)
}

// silently ignore
settingsStore.delete('version')

Implementation of ​

IStore.validate

values ​

values: This["values"]

Defined in: store/src/Store.ts:663

Get all values as an array

Implementation of ​

IStore.values

write ​

write: This["write"]

Defined in: store/src/Store.ts:665

Write data to the underlying storage (localStorage or file).

Param ​

data

(optional) Data to write.

  • If provided, it overwrites the storage.
  • If not provided, the current in-memory data is used (if cache is enabled).

Param ​

silent

(optional) Whether to throw error on failure. Default: true if delay

Returns ​

true if the write was successful, false otherwise.

Implementation of ​

IStore.write

Accessors ​

size ​

Get Signature ​

get size(): number

Defined in: store/src/Store.ts:243

Get the number of items

Returns ​

number

Get the number of items

Implementation of ​

IStore.size

Methods ​

forceUpdateCache() ​

static forceUpdateCache(name): void

Defined in: store/src/Store.ts:357

Trigger forced update of cached data from storage.

Parameters ​

name ​

string | true | string[]

determines which cache-enabled storage instances to be updated.

  • name (string | string[]): update all instances with a specific name(s)
  • global (true): update all instances globally

See forceUpdateCache$ for more details.

Returns ​

void