README.md
<h1 align="center">
LaterMom?
</h1>
<div align="center">
[![npm version](https://badge.fury.io/js/latermom.svg)](https://badge.fury.io/js/latermom) [![Known Vulnerabilities](https://snyk.io/test/github/Prozi/latermom/badge.svg?targetFile=package.json)](https://snyk.io/test/github/Prozi/latermom?targetFile=package.json)
</div>
<p align="center">
You know when you were a kid and mom told you to clean your room,<br/>
when you was busy with something else, your answer would always be the same.
</p>
<p align="center">
This library is the universal 0 dependencies lazy cache implementation,<br/>
leveraging usage of es6 data structures.
</p>
## Installation
`yarn add latermom --save`
## Usage
```javascript
const { Cache } = require("latermom")
const maxSize = 2 // will limit max cache size upon cache.get()
const getUser = async (id) => {
const response = await fetch("https://dummyjson.com/users/" + id)
const { firstName, lastName, address } = await response.json()
return {
id,
name: `${firstName} ${lastName}`,
address,
}
}
const usersCached = new Cache(getUser, maxSize)
Promise.all([
usersCached.get(1),
usersCached.get(2),
usersCached.get(3),
usersCached.get(4),
]).then((users) => {
console.log(usersCached.data) // contains only last maxSize users (3 and 4)
console.log(usersCached.size) // 2
})
```
```javascript
const { Cache } = require("latermom")
// create cache with factory function (may take any number of parameters)
const cache = new Cache(() => Math.random())
// each time you call the cache.get with same parameters
// you will get the same once lazy cached answer
const a = cache.get(1, 2, 3)
const b = cache.get(1, 2, 3) // this will return the same as above
const c = cache.get(1, 2)
const d = cache.get(1, 2, 4)
console.log(a === b) // true
console.log(a !== c) // true
console.log(a !== d) // true
```
## API
```typescript
class Cache<T = unknown> {
constructor(factoryFunction: (...args: any[]) => T, maxSize: number = Infinity) {
//
}
}
```
- creates a LaterMom (Lazy Map) instance with factory function for lazy cache
methods
- `get(...args: any[]): T` - get entry at key created from args, lazy instantiated by factory
- `createKey(...args: any[]): string` - creates string key
- `create(...args: any[]): T` - wrapped factory function
- `hasKey(key: string): boolean` - check if has entry at key
- `has(...args: any[]): boolean` - check if has entry at key created from args
- `deleteKey(key: string): boolean` - deletes entry from data at key
- `delete(...args): boolean` - deletes entry from data at key created from args
- `size: number` - returns size of data
- `maxSize: number` - on insert the oldest items are deleted until reached maxSize
properties:
- data: Map
## Tests
```bash
$ jest
PASS ./index.test.js
✓ Calls factory once when asked for same key many times (62 ms)
✓ Getter is able to handle multiple arguments
✓ Readme has working code (1 ms)
Test Suites: 1 passed, 1 total
Tests: 3 passed, 3 total
Snapshots: 0 total
Time: 0.946 s, estimated 1 s
Ran all test suites.
Done in 1.44s.
```
## License
MIT
## Author
Jacek Pietal @ 2019-2021