locustjs-random

This library helps in producing random sequence of characters.

Installation

npm i @locustjs/random

Types

RandomGeneratorBase

It is an abstract class that defines structure of random classes. It currently has a default RandomGeneratorDefault implementation.

Methods

next(min, max)

Generates a new random number between min (inclusive) and max (exclusive).

const random = new RandomGeneratorDefault();

for (let i = 0; i < 10; i++) {
  const s = random.next(10, 100);
    
    console.log(s);
}

/*
12
25
67
34
19
81
44
73
25
31
*/

generate(options)

Generates a new random sequence based on the given options.

options is an object with the properties described below:

| Property | Type | Description | Default | |----------|-----|--------|------| | type | string, number, RandomType | specifies type of random sequence based on different values RandomType enum provides (listed in next table). | 'num' | | minLen | number | minimum sequence length. Used when generating a random sequence of characters with random length between minLen and maxLen | 5 | | maxLen | number | maximum sequence length. | 7 | | len | number | explicit fixed sequence length. | undefined | | from | number | starting number. Used when generating random numbers (when type is num). | | | to | number | ending random number. Used when generating random numbers (when type is num). | | | chars | array | List of characters to be used to produce random characters. | [ ] | | excludes | list of characters that should be excluded when generating random sequence. | [ ] |

RandomType enum values

| type | description | value | |----------|:-------------:|:---:| | num | numeric | 0 | | alpha | english alphabet letters, uppercase and lowercase | 1 | | alphaNum | alphabet letters and numeric | 2 | | upper | only uppercase letters | 3 | | lower | only lowercase letters | 4 | | upperNum | uppercase letters and numbers | 5 | | lowerNum | lowercase letters and numbers | 6 | | custom | custom characters. requires settings 'chars'. | 7 |

Example:

import { RandomGeneratorDefault, RandomType } from '@locustjs/random';

const random = new RandomGeneratorDefault();

for (let i = 0; i < 10; i++) {
  const s = random.generate({
    type: RandomType.alphaNum,
    len: 10
  });
    
    console.log(s);
}

Result:

f0ivY4eJwH
nzLkl5s80k
9G5RjUK96j
9ppD91iehG
ze1a10M3l7
xyN00yi1YV
oENcb7w85E
P72zCw361S
50tJcr1m9c
N262uQBZJ9

Random static class

There is a static helper class named Random that simplifies generating random sequences.

var s1 = Random.generate({ type: 'alpha', len: 10 });
var s2 = Random.generate({ type: 'num', from: 1000, to: 9999 });
var s3 = Random.generate({ type: 'custom', chars: ['a', 'b', 'c', 'x', 'y', 'z', '1', '2', '3' ], len: 5 });

Random has a static instance property that is used internally by static generate and next methods. By default Random.instance is set with an instance of RandomGeneratorDefault, however, it is a setter property and can be set with an instance of any subclass of RandomGeneratorBase, enabling developer to use his own implementation of random sequence generator.

class MyRandomGenerator extends RandomGeneratorBase {
  ...
}

Random.instance = new MyRandomGenerator()

console.log(Random.generate({ type: 'alpha' }))