IsomorphicStore 中文

1. Introduction

IsomorphicStore is a lightweight and flexible TypeScript storage library that provides a consistent data storage API for browser environments. Regardless of whether the underlying storage mechanism is localStorage, sessionStorage, history state, navigation state, or in-memory storage, you can access data through a unified interface without modifying business logic.

Key Features:

• Multiple Adapter Support — Five built-in storage strategies available out of the box for quick backend switching.
• Namespace Isolation — Prevents data conflicts between different modules or applications.
• Event System — Subscribe to data changes and respond in real-time.
• Version Management and Migration — Automatically transforms data during upgrades without manual compatibility code.
• Comprehensive Error Handling — Custom error classes for convenient debugging.
• Native TypeScript Support — Complete type safety.

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2. Core Concepts

Storage Strategies

IsomorphicStore supports five storage strategies, each representing different lifecycles:

Strategy	Storage Location	Lifecycle	Capacity	Use Cases
LOCAL	localStorage	Cross-session, cross-tab persistence	5-10MB	User preferences, settings, long-term cache
SESSION	sessionStorage	Current tab session	5-10MB	Temporary session data, temporary state
MEMORY	Memory heap	Page runtime	Unlimited	Computation cache, performance optimization, temporary data
HISTORY	history.state	Current history entry	Same-origin limit	Page navigation state, form recovery
NAVIGATION	navigation.currentEntry.state	Current navigation entry (new API)	Same-origin limit	Modern Web App navigation state

Core Principles

1. Strategy Binding: Each IsomorphicStore instance specifies a strategy during construction, and all subsequent operations use this strategy.
2. Namespace Isolation: Each IsomorphicStore has its own isolated namespace to prevent data conflicts between different modules or applications.
3. Conflict Detection: The same namespace cannot be occupied by multiple IsomorphicStore instances; otherwise, an error is thrown. Pass reuse: true in options to override this check.
4. Cross-Storage Coordination: If your business requires operations across different storage strategies, create multiple IsomorphicStore instances and coordinate them manually.
5. Automatic Initialization: The storage location is automatically initialized during construction to ensure data structure integrity.

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3. Installation

Install using your preferred package manager:

npm install isomorphic-store

Or:

pnpm add isomorphic-store
yarn add isomorphic-store

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4. Usage

4.1 Basic Example

Define a schema, create a store, and perform CRUD operations:

import { IsomorphicStore, StorageStrategy } from 'isomorphic-store';

type AppSchema = {
  username: string;
  theme: 'light' | 'dark';
};

const store = new IsomorphicStore<AppSchema>('my-app:state', StorageStrategy.MEMORY);

store.set('username', 'Alice');
store.set('theme', 'dark');

console.log(store.get('username')); // 'Alice'

store.remove('theme');
store.clear();
store.destroy();

4.2 Storage Strategies

IsomorphicStore provides five built-in storage strategies. Choose based on your requirements:

4.2.1 LOCAL (localStorage)

Data persists across browser sessions. Suitable for long-term configurations and user preferences.

type SettingsSchema = { theme: string };
const settings = new IsomorphicStore<SettingsSchema>('settings', StorageStrategy.LOCAL);
settings.set('theme', 'dark');

4.2.2 SESSION (sessionStorage)

Session-scoped persistence. Data is cleared when the tab closes. Suitable for session-level temporary data.

type SessionSchema = { authToken: string };
const session = new IsomorphicStore<SessionSchema>('session', StorageStrategy.SESSION);
session.set('authToken', 'abc123');

4.2.3 MEMORY

In-memory storage cleared when the process terminates. Suitable for application runtime-only temporary state.

type CacheSchema = { cachedList: number[] };
const cache = new IsomorphicStore<CacheSchema>('cache', StorageStrategy.MEMORY);
cache.set('cachedList', [1, 2, 3]);

4.2.4 HISTORY (history.state)

Uses the browser History API, integrated with routing. Suitable for intermediate workflow states.

type FlowSchema = { currentStep: number };
const flow = new IsomorphicStore<FlowSchema>('flow', StorageStrategy.HISTORY);
flow.set('currentStep', 2);

4.2.5 NAVIGATION (navigation.state)

Asynchronous Navigation API for cross-tab navigation context.

type NavSchema = { destination: string };
const nav = new IsomorphicStore<NavSchema>('nav', StorageStrategy.NAVIGATION);
nav.set('destination', '/home');

4.3 Event Subscription

Monitor data changes and respond in real-time:

type AppSchema = { count: number };
const store = new IsomorphicStore<AppSchema>('app', StorageStrategy.MEMORY);

// Subscribe to all changes
const unsubscribe = store.on(event => {
  console.log(`Event: ${event.type}`);
  console.log(`Key: ${event.key}`);
  console.log(`Old Value: ${event.oldValue}`);
  console.log(`New Value: ${event.newValue}`);
});

store.set('count', 1); // Triggers subscription

// Subscribe to a specific key
const unsubKey = store.onKey('count', event => {
  console.log(`Count changed to ${event.newValue}`);
});

unsubscribe();
unsubKey();

4.4 Versioning and Migration

When the data schema undergoes breaking changes, IsomorphicStore can automatically migrate data at construction time. The version number defaults to 0, representing an initial state without versioning.

Basic Usage

// Assume existing version 0 data (no version specified means default 0)
const store = new IsomorphicStore('user', StorageStrategy.LOCAL);
store.set('profile', { name: 'Alice', age: 25 });
store.destroy();

// Upgrade to version 1 with a 0→1 migration rule
const storeV1 = new IsomorphicStore('user', StorageStrategy.LOCAL, {
  version: 1,
  migrations: [
    {
      from: 0,
      to: 1,
      migrate: (data) => ({
        profile: {
          ...data.profile,
          joinedAt: Date.now()
        }
      })
    }
  ]
});

storeV1.get('profile'); // { name: 'Alice', age: 25, joinedAt: 1709... }

Chained Migrations

Migration chains must be contiguous — a migration rule is required for each step from one version to the next:

const storeV3 = new IsomorphicStore('app', StorageStrategy.LOCAL, {
  version: 3,
  migrations: [
    {
      from: 0,
      to: 1,
      migrate: (data) => ({ ...data, v1: true })
    },
    {
      from: 1,
      to: 2,
      migrate: (data) => ({ ...data, v2: true })
    },
    {
      from: 2,
      to: 3,
      migrate: (data) => ({ ...data, v3: true })
    }
  ]
});

Migration Rules

• The migration function receives all data in the namespace (Record<string, any>) and must return the complete migrated data.
• The migrate function replaces all keys in the namespace; any unreturned keys will be removed.
• If the stored version is >= the current version, no migration is executed.
• If there is no stored version and no data, only the current version number is written.
• Missing intermediate migration rules will throw a MigrationError.

4.5 Namespacing

Each IsomorphicStore instance isolates data through namespaces, preventing conflicts:

type UserSchema = { name: string };
type SettingsSchema = { theme: string };

const userStore = new IsomorphicStore<UserSchema>('user:profile', StorageStrategy.LOCAL);
const settingsStore = new IsomorphicStore<SettingsSchema>('app:settings', StorageStrategy.LOCAL);

userStore.set('name', 'Alice');
settingsStore.set('theme', 'dark');

console.log(userStore.get('name'));   // 'Alice'
console.log(settingsStore.get('theme')); // 'dark'
console.log(userStore.get('theme'));  // null — different namespace

4.6 TypeScript Usage

IsomorphicStore<T> requires T to be a record type mapping keys to their value types (a "schema"). TypeScript infers exact types per key:

type AppSchema = {
  user: { id: number; name: string };
  theme: 'light' | 'dark';
  isLoggedIn: boolean;
};

const store = new IsomorphicStore<AppSchema>('app', StorageStrategy.LOCAL);

store.set('user', { id: 1, name: 'Alice' }); // type-safe
store.set('theme', 'dark');                   // type-safe
// store.set('theme', 'invalid');             // compile error

const user = store.get('user'); // { id: number; name: string } | null

// Key names are also type-checked
store.remove('theme');    // OK
// store.remove('unknown'); // compile error

For dynamic keys, use an index signature:

type DynamicSchema = { [key: string]: unknown };
const store = new IsomorphicStore<DynamicSchema>('dynamic', StorageStrategy.MEMORY);

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5. API Reference

IsomorphicStore Class

class IsomorphicStore<T extends Record<string, any>>

Constructor

constructor(
  namespace: string,
  strategy: StorageStrategy | string,
  options?: IsomorphicStoreOptions
)

• namespace (string): Namespace identifier. Stores with the same namespace share data.
• strategy (StorageStrategy | string): Storage strategy or custom adapter name.
• options:
  • version (number): Data version, defaults to 0.
  • migrations (MigrationRule[]): Version migration rules.
  • reuse (boolean): If true, reuse an already-registered namespace instead of throwing a conflict error.

Methods

set<K extends keyof T & string>(key: K, value: T[K]): void

Sets or updates a data item. The key and value types are inferred from the schema.

get<K extends keyof T & string>(key: K): T[K] | null

Retrieves a data item. Executes version migration if needed.

remove<K extends keyof T & string>(key: K): void

Removes a specific data item.

clear(): void

Clears all data within the namespace.

hasKey<K extends keyof T & string>(key: K): boolean

Checks if a data item exists.

getOrDefault<K extends keyof T & string>(key: K, defaultValue: T[K]): T[K]

Gets a data item, returns defaultValue if not found.

on(listener: EventListener): Unsubscribe

Subscribes to all data change events.

off(listener: EventListener): void

Unsubscribes from all data change events.

onKey<K extends keyof T & string>(key: K, listener: EventListener<T[K]>): Unsubscribe

Subscribes to change events for a specific key.

offKey<K extends keyof T & string>(key: K, listener: EventListener<T[K]>): void

Unsubscribes from change events for a specific key.

once(listener: EventListener): Unsubscribe

Subscribes to the next data change event only.

onceKey<K extends keyof T & string>(key: K, listener: EventListener<T[K]>): Unsubscribe

Subscribes to the next change event for a specific key only.

destroy(): void

Destroys the store instance and unloads all listeners.

Event Object

interface IsomorphicStoreEvent<V> {
  type: IsomorphicStoreEventType; // 'set' | 'remove' | 'clear'
  key?: string;
  oldValue?: V | null | undefined;
  newValue?: V | null | undefined;
  namespace: string;
  timestamp: number;
  source: any;
}

Error Types

class IsomorphicStoreError extends Error { }
class NamespaceConflictError extends IsomorphicStoreError { }
class MigrationError extends IsomorphicStoreError { }
class SerializationError extends IsomorphicStoreError { }
class StorageQuotaExceededError extends IsomorphicStoreError { }
class UnsupportedStrategyError extends IsomorphicStoreError { }

Exported Types

import {
  IsomorphicStore,
  StorageStrategy,
  IsomorphicStoreEvent,
  IsomorphicStoreEventType,
  IsomorphicStoreOptions,
  MigrationRule,
  EventListener,
  Unsubscribe,
  IStorageAdapter,
  globalNamespaceRegistry
} from 'isomorphic-store';

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6. License

MIT License

Copyright (c) 2025

This project is licensed under the MIT License, allowing free use, modification, and distribution. See the LICENSE file for details.

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For more information and examples, visit the GitHub repository.