File: /var/dev/shahnamag/back-end/node_modules/lru.min/README.md
<h1 align="center">lru.min</h1>
<div align="center">
[](https://www.npmjs.com/package/lru.min)
[](https://www.npmjs.com/package/lru.min)
[](https://app.codecov.io/gh/wellwelwel/lru.min)<br />
[](https://github.com/wellwelwel/lru.min/actions/workflows/ci_node.yml?query=branch%3Amain)
[](https://github.com/wellwelwel/lru.min/actions/workflows/ci_bun.yml?query=branch%3Amain)
[](https://github.com/wellwelwel/lru.min/actions/workflows/ci_deno.yml?query=branch%3Amain)
🔥 An extremely fast, efficient, and lightweight <strong><a href="https://en.m.wikipedia.org/wiki/Cache_replacement_policies#Least_Recently_Used_.28LRU.29">LRU</a> Cache</strong> for <strong>JavaScript</strong> (<strong>Browser</strong> compatible).
</div>
## Why another LRU?
- 🎖️ **lru.min** is fully compatible with both **Node.js** _(8+)_, **Bun**, **Deno** and, browser environments. All of this, while maintaining the same high performance [_(and a little more)_](https://github.com/wellwelwel/lru.min?tab=readme-ov-file#performance) as the most popular **LRU** packages.
---
## Install
```bash
# Node.js
npm i lru.min
```
```bash
# Bun
bun add lru.min
```
```bash
# Deno
deno add npm:lru.min
```
---
## Usage
### Quickstart
```js
import { createLRU } from 'lru.min';
const max = 2;
const onEviction = (key, value) => {
console.log(`Key "${key}" with value "${value}" has been evicted.`);
};
const LRU = createLRU({
max,
onEviction,
});
LRU.set('A', 'My Value');
LRU.set('B', 'Other Value');
LRU.set('C', 'Another Value');
// => Key "A" with value "My Value" has been evicted.
LRU.has('B');
LRU.get('B');
LRU.delete('B');
// => Key "B" with value "Other Value" has been evicted.
LRU.peek('C');
LRU.clear(); // ← recommended | LRU.evict(max) → (slower alternative)
// => Key "C" with value "Another Value" has been evicted.
LRU.set('D', "You're amazing 💛");
LRU.size; // 1
LRU.max; // 2
LRU.available; // 1
LRU.resize(10);
LRU.size; // 1
LRU.max; // 10
LRU.available; // 9
```
> For _up-to-date_ documentation, always follow the [**README.md**](https://github.com/wellwelwel/lru.min?tab=readme-ov-file#readme) in the **GitHub** repository.
### Import
#### ES Modules
```js
import { createLRU } from 'lru.min';
```
#### CommonJS
```js
const { createLRU } = require('lru.min');
```
#### Browser
> Requires **ES6**.
```html
<script src="https://cdn.jsdelivr.net/npm/lru.min@1.x.x/browser/lru.min.js"></script>
```
- You can use tools such as [**Babel**](https://github.com/babel/babel) to increase the compatibility rate.
### Create a new LRU Cache
> Set maximum size when creating **LRU**.
```ts
const LRU = createLRU({ max: 150_000 });
```
Also, you can set a callback for every deletion/eviction:
```ts
const LRU = createLRU({
max: 150_000,
onEviction: (key, value) => {
// do something
},
});
```
### Set a cache
Adds a key-value pair to the cache. Updates the value if the key already exists
```ts
LRU.set('key', 'value');
```
> `undefined` keys will simply be ignored.
- Complexity: **O(1)**.
### Get a cache
Retrieves the value for a given key and moves the key to the most recent position.
```ts
LRU.get('key');
```
- Complexity: **O(1)**.
### Peek a cache
Retrieves the value for a given key without changing its position.
```ts
LRU.peek('key');
```
- Complexity: **O(1)**.
### Check if a key exists
```ts
LRU.has('key');
```
- Complexity: **O(1)**.
### Delete a cache
```ts
LRU.delete('key');
```
- Complexity: **O(1)**.
### Evict from the oldest cache
Evicts the specified number of the oldest items from the cache.
```ts
LRU.evict(1000);
```
- Complexity: **O(key)** — even if passed a number greater than the number of items, only existing items will be evicted.
> [!TIP]
>
> - Methods that perform eviction(s) when maximum size is reached: `set` and `resize`.
> - Methods that always perform eviction(s): `delete`, `clear`, and `evict` itself.
### Resize the cache
Resizes the cache to a new maximum size, evicting items if necessary.
```ts
LRU.resize(50_000);
```
- Complexity:
- Increasing: **O(newMax - max)**.
- Downsizing: **O(n)**.
### Clear the cache
Clears and disposes (if used) all key-value pairs from the cache.
```ts
LRU.clear();
```
- Complexity:
- Without `onEviction`: **O(1)**.
- Using `onEviction`: **O(entries)**.
### Debugging
#### Get the max size of the cache
```ts
LRU.max;
```
- Complexity: **O(1)**.
#### Get the current size of the cache
```ts
LRU.size;
```
- Complexity: **O(1)**.
#### Get the available slots in the cache
```ts
LRU.available;
```
- Complexity: **O(1)**.
### Iterating the cache
#### Get all keys
Iterates over all keys in the cache, from most recent to least recent.
```ts
const keys = [...LRU.keys()];
```
- Complexity: **O(keys)**.
#### Get all values
Iterates over all values in the cache, from most recent to least recent.
```ts
const values = [...LRU.values()];
```
- Complexity: **O(values)**.
#### Get all entries
Iterates over `[key, value]` pairs in the cache, from most recent to least recent.
```ts
const entries = [...LRU.entries()];
```
- Complexity: **O(entries)**.
#### Run a callback for each entry
Iterates over each value-key pair in the cache, from most recent to least recent.
```ts
LRU.forEach((value, key) => {
// do something
});
```
- Complexity: **O(entries)**.
---
> [!NOTE]
>
> - We use `O(keys)`, `O(values)`, `O(entries)`, and `O(newMax - max)` to explicitly indicate what is being iterated over. In traditional complexity notation, this would be represented as `O(n)`.
---
### TypeScript
You can set types for both keys and values. For example:
```ts
import { createLRU } from 'lru.min';
type Key = number;
type Value = {
name: string;
};
const LRU = createLRU<Key, Value>({ max: 1000 });
LRU.set(1, { name: 'Peter' });
LRU.set(2, { name: 'Mary' });
```
Also:
```ts
import { createLRU, type CacheOptions } from 'lru.min';
type Key = number;
type Value = {
name: string;
};
const options: CacheOptions<Key, Value> = {
max: 10,
onEviction(key, value) {
console.log(key, value);
},
};
// No need to repeat the type params
const LRU = createLRU(options);
LRU.set(1, { name: 'Peter' });
LRU.set(2, { name: 'Mary' });
```
---
### Performance
The benchmark is performed by comparing `1,000,000` runs through a maximum cache limit of `100,000`, getting `333,333` caches and deleting `200,000` keys 10 consecutive times, clearing the cache every run.
> - [**lru-cache**](https://github.com/isaacs/node-lru-cache) `v11.0.0`
> - [**quick-lru**](https://github.com/sindresorhus/quick-lru) `v7.0.0`
```sh
# Time:
lru.min: 240.45ms
lru-cache: 258.32ms
quick-lru: 279.89ms
# CPU:
lru.min: 275558.30µs
lru-cache: 306858.30µs
quick-lru: 401318.80µs
```
- See detailed results and how the tests are run and compared in the [**benchmark**](https://github.com/wellwelwel/lru.min/tree/main/benchmark) directory.
---
## Security Policy
[](https://github.com/wellwelwel/lru.min/actions/workflows/ci_codeql.yml?query=branch%3Amain)
Please check the [**SECURITY.md**](https://github.com/wellwelwel/lru.min/blob/main/SECURITY.md).
---
## Contributing
See the [**Contributing Guide**](https://github.com/wellwelwel/lru.min/blob/main/CONTRIBUTING.md) and please follow our [**Code of Conduct**](https://github.com/wellwelwel/lru.min/blob/main/CODE_OF_CONDUCT.md) 🚀
---
## Acknowledgements
**lru.min** is based and inspired on the architecture and code of both [**lru-cache**](https://github.com/isaacs/node-lru-cache) and [**quick-lru**](https://github.com/sindresorhus/quick-lru), simplifying their core concepts for enhanced performance and compatibility.
For more comprehensive features such as **TTL** support, consider using and supporting them 🤝
- The architecture is mostly based on [@isaacs](https://github.com/isaacs) — [**lru-cache**](https://github.com/isaacs/node-lru-cache/blob/8f51d75351cbb4ac819952eb8e9f95eda00ef800/src/index.ts).
- Most of the methods names and its functionalities were inspired by [@sindresorhus](https://github.com/sindresorhus) — [**quick-lru**](https://github.com/sindresorhus/quick-lru/blob/a2262c65e1952539cb4d985a67c46363a780d234/index.js).
- [](https://github.com/wellwelwel/lru.min/graphs/contributors)
---
#### What comes from [**lru-cache**](https://github.com/isaacs/node-lru-cache)?
Architecture's essence:
> _It's not the same code, but majority based on [this](https://github.com/isaacs/node-lru-cache/blob/8f51d75351cbb4ac819952eb8e9f95eda00ef800/src/index.ts#L1385-L1394)._
```ts
let free: number[] = [];
const keyMap: Map<Key, number> = new Map();
const keyList: (Key | undefined)[] = new Array(max).fill(undefined);
const valList: (Value | undefined)[] = new Array(max).fill(undefined);
const next: number[] = new Array(max).fill(0);
const prev: number[] = new Array(max).fill(0);
```
---
#### What comes from [**quick-lru**](https://github.com/sindresorhus/quick-lru)?
Name of methods and options _(including their final functionality ideas)_:
- `resize`
- `peek`
- `onEviction`
- `forEach`
- `entriesDescending` as `entries`
---
## License
**lru.min** is under the [**MIT License**](https://github.com/wellwelwel/lru.min/blob/main/LICENSE).<br />
Copyright © 2024-present [Weslley Araújo](https://github.com/wellwelwel) and **lru.min** [contributors](https://github.com/wellwelwel/lru.min/graphs/contributors).