A simple memorise function that uses a fast LRU cache under the hood.
!Build
> A simple memorise function that uses a fast LRU cache under the hood.
- Works in Node and the browser
- Memorises both sync and async functions.
- Automatic cache key generation from function arguments
- Cache TTL / value expiry
- Fully typed: memorised functions inherit their source function types.
- Bring your own cache or cache-keygen function, or we create one for you.
- Cache is exposed for the memorised function, if you want to access it and modify or manually clear.
``ts
import memorise from "lru-memorise";
const answerMyToughQuestion = (question: string) => {
// ... heavy compute
return response;
};
const memorisedFn = memorise(answerMyToughQuestion);
memorisedFn(What's the meaning of life?); // Calls source fn, response cached #1.Are you an AI?
memorisedFn(); // Calls source fn, response cached #2.
memorisedFn(What's the meaning of life?); // Returns cached value #1Are you an AI?
memorisedFn(); // Returns cached value #2`
> Note, all options are optional
| Option | Default | Description |
| ---------------- | --------------- | --------------------------------------------------------------------------------------------------------- |
| cache | undefined | Bring your own LRU cache, as long as it supports standard set and get operations |{ max: 1000 }
| cacheKeyResolver | defaultFn | Function used to generate unique cache key from arguments. Takes array of arguments, and return a string. |
| lruOptions | | Default options for tiny-lru. The two options are max and ttl. |
Under the hood we use tiny-lru, but you can bring your own, or create your cache outside and use it.
If you don't provide one, we create a cache for you. This cache is exposed through the _cache function, if you want to have access to it.
We have a simple function to generate a cache key from function arguments, using JSON.stringify. You can of course pass your own custom one if you have a more complex situation, or want to cache to behave differently. It should return a string.
`ts`
type Resolver = (...args: any[]) => string;
By default, we limit the max cache size to 1000 keys, and we don't set a TTL on the key values.
`ts``
Type LRUOPtions = {
max: number // Max number of keys in Cache
ttl: number // Expiry of items in cache
}