SQLite Cache

A high-performance, type-safe SQLite-based cache for Node.js applications with built-in TTL (Time To Live), size limits, and schema validation.

Features

• 🚀 High Performance: Built on Node.js native SQLite driver
• 🔒 Type Safe: Full TypeScript support with generic types
• ⏰ TTL Support: Automatic expiration with configurable time-to-live
• 📏 Size Limits: LRU-style eviction when max entries exceeded
• 🔍 Schema Validation: JSON Schema validation using TypeBox
• 🪵 Built-in Logging: Configurable logging with colorful output
• 🔄 Iterable: Full Map-like interface with iteration support
• 💾 Persistent: Data survives application restarts
• 🧹 Auto Cleanup: Automatic cleanup of expired entries

Requirements

• Node.js >= 22.5.0 (required for native SQLite driver)

Installation

npm install sqlite-cache

Quick Start

import { SQLiteCache } from "sqlite-cache"
import { Type } from "@sinclair/typebox"

// Define your data schema
const UserSchema = Type.Object({
    id: Type.Number(),
    name: Type.String(),
    email: Type.String(),
    active: Type.Boolean()
})

type User = {
    id: number
    name: string
    email: string
    active: boolean
}

// Create cache instance
const cache = new SQLiteCache<string, User>({
    path: "./cache.db",
    schema: UserSchema,
    ttl: 60_000, // 1 minute
    max: 1000, // Maximum 1000 entries
    log: true // Enable logging
})

// Use the cache
const user: User = {
    id: 1,
    name: "John Doe",
    email: "john@example.com",
    active: true
}

cache.set("user:1", user)
const retrieved = cache.get("user:1")
console.log(retrieved) // { id: 1, name: 'John Doe', ... }

// Clean up
cache.close()

API Reference

Constructor

new SQLiteCache<Key extends string, Value extends object>(options: CacheOptions)

Options

Option	Type	Required	Default	Description
path	string	✅	-	Path to SQLite database file
schema	TSchema	✅	-	TypeBox JSON schema for validation
ttl	number	❌	60000	Time to live in milliseconds
max	number	❌	100	Maximum number of entries
log	boolean | LogOptions	❌	false	Logging configuration

Log Options

interface LogOptions {
    prefix?: string // Log prefix (default: '[SQLiteCache]')
    timestamp?: boolean // Include timestamps (default: true)
}

Methods

set(key: Key, value: Value): this

Store a value in the cache with the given key.

cache.set("user:123", { id: 123, name: "Alice", email: "alice@example.com", active: true })

get(key: Key): Value | null

Retrieve a value from the cache. Returns null if not found or expired.

const user = cache.get("user:123")
if (user) {
    console.log(user.name)
}

has(key: Key): boolean

Check if a key exists and is not expired.

if (cache.has("user:123")) {
    console.log("User exists in cache")
}

delete(key: Key): boolean

Remove a specific key from the cache. Returns true if the key existed.

const wasDeleted = cache.delete("user:123")

clear(): void

Remove all entries from the cache.

cache.clear()

close(): void

Close the database connection. Call this when your application shuts down.

cache.close()

Properties

size: number

Get the current number of valid (non-expired) entries in the cache.

console.log(`Cache contains ${cache.size} entries`)

Iteration

The cache implements the iterable protocol and provides Map-like iteration methods:

keys(): IterableIterator<Key>

Iterate over all valid keys.

for (const key of cache.keys()) {
    console.log(key)
}

values(): IterableIterator<Value>

Iterate over all valid values.

for (const user of cache.values()) {
    console.log(user.name)
}

entries(): IterableIterator<[Key, Value]>

Iterate over all valid key-value pairs.

for (const [key, user] of cache.entries()) {
    console.log(`${key}: ${user.name}`)
}

forEach(callback: (value: Value, key: Key, cache: this) => void): void

Execute a callback for each valid entry.

cache.forEach((user, key) => {
    console.log(`Processing ${user.name} with key ${key}`)
})

[Symbol.iterator](): IterableIterator<[Key, Value]>

Direct iteration support.

for (const [key, user] of cache) {
    console.log(`${key}: ${user.name}`)
}

Advanced Usage

Custom Schema with Optional Fields

import { Type } from "@sinclair/typebox"

const ProductSchema = Type.Object({
    id: Type.Number(),
    name: Type.String(),
    price: Type.Number(),
    description: Type.Optional(Type.String()),
    metadata: Type.Optional(
        Type.Object({
            category: Type.String(),
            tags: Type.Array(Type.String()),
            inStock: Type.Boolean()
        })
    )
})

type Product = {
    id: number
    name: string
    price: number
    description?: string
    metadata?: {
        category: string
        tags: string[]
        inStock: boolean
    }
}

const productCache = new SQLiteCache<string, Product>({
    path: "./products.db",
    schema: ProductSchema,
    ttl: 300_000, // 5 minutes
    max: 5000,
    log: {
        prefix: "[ProductCache]",
        timestamp: true
    }
})

Error Handling

try {
    const cache = new SQLiteCache({
        path: "/invalid/path/cache.db",
        schema: UserSchema
    })
} catch (error) {
    console.error("Failed to initialize cache:", error.message)
}

Memory Database

For testing or temporary caching, you can use an in-memory database:

const tempCache = new SQLiteCache<string, User>({
    path: ":memory:",
    schema: UserSchema,
    ttl: 30_000
})

Batch Operations

// Batch insert
const users = [
    { id: 1, name: "Alice", email: "alice@example.com", active: true },
    { id: 2, name: "Bob", email: "bob@example.com", active: false },
    { id: 3, name: "Charlie", email: "charlie@example.com", active: true }
]

users.forEach((user, index) => {
    cache.set(`user:${user.id}`, user)
})

// Batch retrieve
const cachedUsers = users.map((user) => cache.get(`user:${user.id}`)).filter((user) => user !== null)

console.log(`Retrieved ${cachedUsers.length} users from cache`)

Performance Considerations

• Database Location: Use SSD storage for better performance
• TTL Strategy: Shorter TTL reduces memory usage but increases cache misses
• Max Entries: Higher limits improve hit rates but use more storage
• Schema Complexity: Simpler schemas serialize/deserialize faster
• Key Design: Use consistent, predictable key patterns for better organization

Best Practices

1. Proper Cleanup

Always close the cache when your application shuts down:

process.on("SIGINT", () => {
    cache.close()
    process.exit(0)
})

2. Key Naming Conventions

Use consistent key patterns:

// Good
cache.set("user:123", user)
cache.set("product:456", product)
cache.set("session:abc123", session)

// Avoid
cache.set("123", user)
cache.set("prod456", product)
cache.set("sessionabc123", session)

3. Schema Design

Design schemas that match your data structure:

// Prefer this
const UserSchema = Type.Object({
    id: Type.Number(),
    profile: Type.Object({
        name: Type.String(),
        email: Type.String()
    })
})

// Over this (less structured)
const UserSchema = Type.Object({
    id: Type.Number(),
    name: Type.String(),
    email: Type.String()
    // ... many flat properties
})

4. Error Handling

Handle potential errors gracefully:

const user = cache.get("user:123")
if (!user) {
    // Cache miss - fetch from primary data source
    const user = await fetchUserFromDB(123)
    cache.set("user:123", user)
    return user
}
return user

Troubleshooting

Node.js Version Error

Error: "Node version must be 22.5.0 or higher"

Solution: Upgrade to Node.js 22.5.0 or later, which includes the native SQLite driver.

Database Connection Errors

Error: Failed to connect to database

Solutions:

• Ensure the directory exists for file-based databases
• Check file permissions
• Verify disk space availability
• Use :memory: for testing

Schema Validation Errors

Error: Data does not match schema

Solutions:

• Verify your TypeBox schema matches your data structure
• Check for required vs optional fields
• Ensure type compatibility (string vs number, etc.)

Performance Issues

• Use appropriate TTL values
• Monitor cache hit/miss ratios
• Consider database file location (SSD vs HDD)
• Optimize key naming patterns

Contributing

1. Fork the repository
2. Create a feature branch: git checkout -b feature/new-feature
3. Make your changes and add tests
4. Run tests: npm test
5. Commit your changes: git commit -am 'Add new feature'
6. Push to the branch: git push origin feature/new-feature
7. Submit a pull request

License

This project is licensed under the MIT License - see the LICENSE file for details.

Support

• 🐛 Issues: GitHub Issues
• 💖 Sponsor: Patreon

Changelog

v0.0.2

• Initial release with basic caching functionality
• TTL support with automatic cleanup
• Size limits with LRU-style eviction
• TypeBox schema validation
• Full TypeScript support
• Configurable logging
• Map-like iteration interface

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