README.md

cache-manager-function

Cache functions dynamically based on their arguments using cache-manager.

Installation

Install the package using npm:

npm install cache-manager-function

or with Yarn:

yarn add cache-manager-function

Usage

1. Initialize

Call getOrInitializeCache to manually initialize the cache.

const cache = await getOrInitializeCache<RedisStore>({
  store: await redisStore({
    host: 'localhost',
    port: 6379,
  }),
});

Alternatively, you can initialize the cache implicitly by providing the store directly to cachedFunction.

const multiply = (x, y) => x * y;

const cachedMultiply = cachedFunction(multiply, {
  store: await redisStore({
    host: 'localhost',
    port: 6379,
  }),
});

// Initializes the cache and caches the result
await cachedMultiply(2, 3); 

2. Caching with cachedFunction

The selector option specifies which arguments should be used to generate the cache key.

type Person = { name: string; lastname: string };

const greet = (person: Person) => `Hello, ${person.name} ${person.lastname}!`;

// Caches based on `person.name` and `person.lastname`
const cachedGreet = cachedFunction(greet, {
  selector: ['0.name', '0.lastname']
});

await cachedGreet({ person: { name: `John`, lastname: `Doe` } }); // Caches the result based on name=John and lastname=Doe
await cachedGreet({ person: { name: `Jane`, lastname: `Doe` } }); // Caches the result based on name=Jane and lastname=Doe

3. Using the CacheOptions decorator

CacheOptions receives the exact same options that cachedFunction receives. It’s an alternative way to define the cache behavior directly on the function.

import { CacheOptions, cachedFunction } from `cache-manager-function`;

class UserService {
  @CacheOptions(['0'], 300) // Specifies to cache based on the first argument (id), with a TTL of 300ms
  async getUser(id: number) {
    return `User with ID: ${id}`;
  }
}

const service = new UserService();
const cachedFetchUser = cachedFunction(service.getUser);

await userService.getUser(1); // Executes and caches based on the `id` argument
await userService.getUser(1); // Returns the cached result

API

getOrInitializeCache

Initializes or retrieves the cache.

• Parameters:

  • options (Optional): Configuration options to initialize the cache.

• Returns: A promise that resolves to the cache instance.

cachedFunction

Caches the result of a function based on its arguments.

• Parameters:

  • function_: The function to cache.
  • options (Optional): Configuration options for caching.

• Returns: A cached function that returns a promise with the result.

CacheOptions

Decorator to cache function results based on selected arguments.

• Parameters:
  • selector: Paths of the arguments to include in the cache key.
  • ttl (Optional): Time-to-live for the cached result.