@locustjs/random

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' }))