427 lines
10 KiB
Markdown
Executable File
427 lines
10 KiB
Markdown
Executable File
<h1 align="center">lru.min</h1>
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<div align="center">
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[](https://www.npmjs.com/package/lru.min)
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[](https://www.npmjs.com/package/lru.min)
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[](https://app.codecov.io/gh/wellwelwel/lru.min)<br />
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[](https://github.com/wellwelwel/lru.min/actions/workflows/ci_node.yml?query=branch%3Amain)
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[](https://github.com/wellwelwel/lru.min/actions/workflows/ci_bun.yml?query=branch%3Amain)
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[](https://github.com/wellwelwel/lru.min/actions/workflows/ci_deno.yml?query=branch%3Amain)
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🔥 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).
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</div>
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## Why another LRU?
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- 🎖️ **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.
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---
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## Install
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```bash
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# Node.js
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npm i lru.min
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```
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```bash
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# Bun
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bun add lru.min
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```
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```bash
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# Deno
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deno add npm:lru.min
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```
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---
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## Usage
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### Quickstart
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```js
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import { createLRU } from 'lru.min';
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const max = 2;
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const onEviction = (key, value) => {
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console.log(`Key "${key}" with value "${value}" has been evicted.`);
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};
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const LRU = createLRU({
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max,
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onEviction,
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});
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LRU.set('A', 'My Value');
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LRU.set('B', 'Other Value');
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LRU.set('C', 'Another Value');
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// => Key "A" with value "My Value" has been evicted.
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LRU.has('B');
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LRU.get('B');
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LRU.delete('B');
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// => Key "B" with value "Other Value" has been evicted.
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LRU.peek('C');
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LRU.clear(); // ← recommended | LRU.evict(max) → (slower alternative)
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// => Key "C" with value "Another Value" has been evicted.
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LRU.set('D', "You're amazing 💛");
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LRU.size; // 1
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LRU.max; // 2
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LRU.available; // 1
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LRU.resize(10);
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LRU.size; // 1
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LRU.max; // 10
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LRU.available; // 9
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```
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> 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.
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### Import
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#### ES Modules
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```js
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import { createLRU } from 'lru.min';
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```
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#### CommonJS
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```js
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const { createLRU } = require('lru.min');
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```
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#### Browser
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> Requires **ES6**.
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```html
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<script src="https://cdn.jsdelivr.net/npm/lru.min@1.x.x/browser/lru.min.js"></script>
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```
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- You can use tools such as [**Babel**](https://github.com/babel/babel) to increase the compatibility rate.
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### Create a new LRU Cache
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> Set maximum size when creating **LRU**.
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```ts
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const LRU = createLRU({ max: 150_000 });
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```
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Also, you can set a callback for every deletion/eviction:
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```ts
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const LRU = createLRU({
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max: 150_000,
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onEviction: (key, value) => {
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// do something
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},
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});
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```
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### Set a cache
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Adds a key-value pair to the cache. Updates the value if the key already exists
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```ts
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LRU.set('key', 'value');
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```
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> `undefined` keys will simply be ignored.
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- Complexity: **O(1)**.
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### Get a cache
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Retrieves the value for a given key and moves the key to the most recent position.
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```ts
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LRU.get('key');
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```
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- Complexity: **O(1)**.
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### Peek a cache
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Retrieves the value for a given key without changing its position.
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```ts
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LRU.peek('key');
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```
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- Complexity: **O(1)**.
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### Check if a key exists
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```ts
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LRU.has('key');
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```
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- Complexity: **O(1)**.
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### Delete a cache
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```ts
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LRU.delete('key');
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```
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- Complexity: **O(1)**.
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### Evict from the oldest cache
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Evicts the specified number of the oldest items from the cache.
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```ts
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LRU.evict(1000);
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```
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- Complexity: **O(key)** — even if passed a number greater than the number of items, only existing items will be evicted.
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> [!TIP]
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>
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> - Methods that perform eviction(s) when maximum size is reached: `set` and `resize`.
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> - Methods that always perform eviction(s): `delete`, `clear`, and `evict` itself.
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### Resize the cache
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Resizes the cache to a new maximum size, evicting items if necessary.
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```ts
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LRU.resize(50_000);
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```
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- Complexity:
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- Increasing: **O(newMax - max)**.
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- Downsizing: **O(n)**.
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### Clear the cache
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Clears and disposes (if used) all key-value pairs from the cache.
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```ts
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LRU.clear();
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```
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- Complexity:
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- Without `onEviction`: **O(1)**.
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- Using `onEviction`: **O(entries)**.
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### Debugging
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#### Get the max size of the cache
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```ts
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LRU.max;
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```
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- Complexity: **O(1)**.
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#### Get the current size of the cache
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```ts
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LRU.size;
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```
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- Complexity: **O(1)**.
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#### Get the available slots in the cache
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```ts
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LRU.available;
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```
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- Complexity: **O(1)**.
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### Iterating the cache
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#### Get all keys
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Iterates over all keys in the cache, from most recent to least recent.
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```ts
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const keys = [...LRU.keys()];
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```
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- Complexity: **O(keys)**.
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#### Get all values
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Iterates over all values in the cache, from most recent to least recent.
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```ts
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const values = [...LRU.values()];
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```
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- Complexity: **O(values)**.
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#### Get all entries
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Iterates over `[key, value]` pairs in the cache, from most recent to least recent.
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```ts
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const entries = [...LRU.entries()];
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```
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- Complexity: **O(entries)**.
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#### Run a callback for each entry
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Iterates over each value-key pair in the cache, from most recent to least recent.
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```ts
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LRU.forEach((value, key) => {
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// do something
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});
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```
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- Complexity: **O(entries)**.
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---
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> [!NOTE]
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>
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> - 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)`.
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---
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### TypeScript
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You can set types for both keys and values. For example:
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```ts
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import { createLRU } from 'lru.min';
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type Key = number;
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type Value = {
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name: string;
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};
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const LRU = createLRU<Key, Value>({ max: 1000 });
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LRU.set(1, { name: 'Peter' });
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LRU.set(2, { name: 'Mary' });
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```
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Also:
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```ts
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import { createLRU, type CacheOptions } from 'lru.min';
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type Key = number;
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type Value = {
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name: string;
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};
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const options: CacheOptions<Key, Value> = {
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max: 10,
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onEviction(key, value) {
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console.log(key, value);
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},
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};
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// No need to repeat the type params
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const LRU = createLRU(options);
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LRU.set(1, { name: 'Peter' });
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LRU.set(2, { name: 'Mary' });
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```
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---
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### Performance
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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.
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> - [**lru-cache**](https://github.com/isaacs/node-lru-cache) `v11.0.0`
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> - [**quick-lru**](https://github.com/sindresorhus/quick-lru) `v7.0.0`
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```sh
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# Time:
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lru.min: 240.45ms
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lru-cache: 258.32ms
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quick-lru: 279.89ms
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# CPU:
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lru.min: 275558.30µs
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lru-cache: 306858.30µs
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quick-lru: 401318.80µs
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```
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- See detailed results and how the tests are run and compared in the [**benchmark**](https://github.com/wellwelwel/lru.min/tree/main/benchmark) directory.
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---
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## Security Policy
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[](https://github.com/wellwelwel/lru.min/actions/workflows/ci_codeql.yml?query=branch%3Amain)
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Please check the [**SECURITY.md**](https://github.com/wellwelwel/lru.min/blob/main/SECURITY.md).
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---
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## Contributing
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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) 🚀
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---
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## Acknowledgements
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**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.
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For more comprehensive features such as **TTL** support, consider using and supporting them 🤝
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- 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).
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- 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).
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- [](https://github.com/wellwelwel/lru.min/graphs/contributors)
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---
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#### What comes from [**lru-cache**](https://github.com/isaacs/node-lru-cache)?
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Architecture's essence:
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> _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)._
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```ts
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let free: number[] = [];
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const keyMap: Map<Key, number> = new Map();
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const keyList: (Key | undefined)[] = new Array(max).fill(undefined);
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const valList: (Value | undefined)[] = new Array(max).fill(undefined);
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const next: number[] = new Array(max).fill(0);
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const prev: number[] = new Array(max).fill(0);
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```
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---
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#### What comes from [**quick-lru**](https://github.com/sindresorhus/quick-lru)?
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Name of methods and options _(including their final functionality ideas)_:
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- `resize`
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- `peek`
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- `onEviction`
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- `forEach`
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- `entriesDescending` as `entries`
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---
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## License
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**lru.min** is under the [**MIT License**](https://github.com/wellwelwel/lru.min/blob/main/LICENSE).<br />
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Copyright © 2024-present [Weslley Araújo](https://github.com/wellwelwel) and **lru.min** [contributors](https://github.com/wellwelwel/lru.min/graphs/contributors).
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