https://github.com/vitaly-t/prime-lib
Prime number library.
https://github.com/vitaly-t/prime-lib
generators javascript meissel-lehmer prime-numbers rxjs sieve-of-eratosthenes typescript
Last synced: 3 days ago
JSON representation
Prime number library.
- Host: GitHub
- URL: https://github.com/vitaly-t/prime-lib
- Owner: vitaly-t
- License: mit
- Created: 2021-09-26T21:01:23.000Z (over 3 years ago)
- Default Branch: main
- Last Pushed: 2022-09-19T16:08:58.000Z (over 2 years ago)
- Last Synced: 2025-04-09T23:06:42.016Z (24 days ago)
- Topics: generators, javascript, meissel-lehmer, prime-numbers, rxjs, sieve-of-eratosthenes, typescript
- Language: TypeScript
- Homepage:
- Size: 202 KB
- Stars: 12
- Watchers: 2
- Forks: 1
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
- Code of conduct: .github/CODE_OF_CONDUCT.md
Awesome Lists containing this project
README
prime-lib
---------
* [About](#about)
* [Installation](#installation)
* [Usage](#usage)
* [JavaScript](#javascript)
* [TypeScript](#typescript)
* [RXJS](#rxjs)
* [API](#api)
## About
Popular [prime number] functions, implemented in TypeScript, with focus on memory efficiency and performance,
to be friendly for Web apps, and [RXJS] in particular.
It features many well-known optimization methods, such as [Sieve of Eratosthenes], [Meissel Lehmer], etc.
See the following resources:
* [API](#api) - all available functions
* [WiKi] - to help choose a prime generator
* [Benchmarks](./benchmarks) - to see the performance
## Installation
```
$ npm i prime-lib
```
## Usage
Follow the usage examples below, based on your development environment.
### JavaScript
Generating an array with the first 10 primes:
```js
const {generatePrimes, stopOnCount} = require('prime-lib');
const i = generatePrimes(); // create infinite primes iterator
const s = stopOnCount(i, 10); // stop-iterator after 10 values
const values = [...s]; // 2, 3, 5, 7, 11, 13, 17, 19, 23, 29
```
### TypeScript
Generating an array of all primes up to 17:
```js
import {generatePrimes, stopOnValue} from 'prime-lib';
const i = generatePrimes(); // create infinite primes iterator
const s = stopOnValue(i, 17); // stop-iterator when value reaches 17
const values = [...s]; // 2, 3, 5, 7, 11, 13, 17
```
### RXJS
Adding a reusable [RXJS] wrapper first:
```ts
import {Observable, from} from 'rxjs';
import {generatePrimes, IPrimeOptions} from 'prime-lib';
export function primes(options?: IPrimeOptions): Observable {
return from(generatePrimes(options));
}
```
* Generating the first 10 primes:
```ts
import {take} from 'rxjs';
primes().pipe(take(10))
.subscribe(prime => {
// 2, 3, 5, 7, 11, 13, 17, 19, 23, 29
});
```
* Generating 10 primes after 100:
```ts
import {take} from 'rxjs';
primes({start: 100}).pipe(take(10))
.subscribe(prime => {
// 101, 103, 107, 109, 113, 127, 131, 137, 139, 149
});
```
* Maximum-performance, buffered primes generation:
```ts
primes({boost: 10})
.subscribe(prime => {
// 2, 3, 5, 7, 11, 13, 17, 19, 23, 29
});
```
* Detecting primes in another sequence:
```ts
import {range, filter} from 'rxjs';
import {isPrime} from 'prime-lib';
range(0, 20).pipe(filter(a => isPrime(a)))
.subscribe(prime => {
// 2, 3, 5, 7, 11, 13, 17, 19
});
```
## API
#### Prime generators:
* `generatePrimes()` - efficiency-focused, infinite prime generator
* `generatePrimes({start: x})` - efficiency-focused, infinite prime generator, starting from `x`
* `generatePrimes({boost: n})` - performance-focused prime generator, for up to `n` primes
#### Popular prime functions:
* `isPrime(x)` - verifies if `x` is a prime number
* `countPrimes(x)` - precise primes counter, up to `x`, using [Meissel Lehmer algorithm]
* `countPrimesApprox(x)` - instant primes counter, up to `x`, with error margin < 1%
* `primeFactors(x)` - calculates prime factorization
Work-in-progress:
* `nthPrime(n)` - returns prime from index (_**not implemented yet**_)
* `nthPrimeApprox(n)` - returns approximate prime from index (_**not implemented yet**_)
#### Extra helpers:
* `cachePrimes(n)` - creates a gap-compressed cache of `n` primes (see [WiKi])
* `stopOnCount(iterator, count)` - stops the iterator, once `count` has been reached
* `stopOnValue(iterator, maxValue)` - stops the iterator when `maxValue` is exceeded
* `stopWhen(iterator, cb)` - stops the iterator when the callback returns a truthy value
[prime number]:https://en.wikipedia.org/wiki/Prime_number
[Sieve of Eratosthenes]:https://en.wikipedia.org/wiki/Sieve_of_Eratosthenes
[WiKi]:https://github.com/vitaly-t/prime-lib/wiki
[RXJS]:https://github.com/ReactiveX/rxjs
[Meissel Lehmer]:https://en.wikipedia.org/wiki/Meissel%E2%80%93Lehmer_algorithm
[Meissel Lehmer algorithm]:https://en.wikipedia.org/wiki/Meissel%E2%80%93Lehmer_algorithm