| 1 | const crypto = require('crypto') |
| 2 | |
| 3 | /** |
| 4 | * Generate a cryptographically secure random number in the [0,1[ range |
| 5 | * |
| 6 | * @returns |
| 7 | */ |
| 8 | function secureRandom () { |
| 9 | return crypto.randomBytes(4).readUInt32LE() / 0x100000000 |
| 10 | } |
| 11 | |
| 12 | /** |
| 13 | * @param max |
| 14 | * @param min |
| 15 | * @returns |
| 16 | */ |
| 17 | function generateRandomInteger (max = Number.MAX_SAFE_INTEGER, min = 0) { |
| 18 | if (max < min || max < 0 || min < 0) { |
| 19 | throw new RangeError('Invalid interval') |
| 20 | } |
| 21 | max = Math.floor(max) |
| 22 | if (min != null && min !== 0) { |
| 23 | min = Math.ceil(min) |
| 24 | return Math.floor(secureRandom() * (max - min + 1)) + min |
| 25 | } |
| 26 | return Math.floor(secureRandom() * (max + 1)) |
| 27 | } |
| 28 | |
| 29 | /** |
| 30 | * |
| 31 | * @param max |
| 32 | * @param min |
| 33 | * @param negative |
| 34 | * @returns |
| 35 | */ |
| 36 | function generateRandomFloat (max = Number.MAX_VALUE, min = 0, negative = true) { |
| 37 | if (max < min || max < 0 || min < 0) { |
| 38 | throw new RangeError('Invalid interval') |
| 39 | } |
| 40 | const randomPositiveFloat = crypto.randomBytes(4).readUInt32LE() / 0xffffffff |
| 41 | const sign = negative && randomPositiveFloat < 0.5 ? -1 : 1 |
| 42 | return sign * (randomPositiveFloat * (max - min) + min) |
| 43 | } |
| 44 | |
| 45 | /** |
| 46 | * |
| 47 | * @param size |
| 48 | * @param max |
| 49 | * @param numberGenerator |
| 50 | * @returns |
| 51 | */ |
| 52 | function generateRandomNumberArray ( |
| 53 | size, |
| 54 | max = Number.MAX_VALUE, |
| 55 | numberGenerator = generateRandomFloat |
| 56 | ) { |
| 57 | const array = [] |
| 58 | for (let i = 0; i < size; i++) { |
| 59 | array.push(numberGenerator(max)) |
| 60 | } |
| 61 | return array |
| 62 | } |
| 63 | |
| 64 | /** |
| 65 | * |
| 66 | * @param sizeMax |
| 67 | * @param numberMax |
| 68 | * @param numberGenerator |
| 69 | * @returns |
| 70 | */ |
| 71 | function generateRandomObject ( |
| 72 | sizeMax = 500, |
| 73 | numberMax = Number.MAX_VALUE, |
| 74 | numberGenerator = generateRandomFloat |
| 75 | ) { |
| 76 | const size = generateRandomInteger(sizeMax) |
| 77 | const object = {} |
| 78 | for (let i = 0; i < size; i++) { |
| 79 | object[i.toString()] = numberGenerator(numberMax) |
| 80 | } |
| 81 | return object |
| 82 | } |
| 83 | |
| 84 | /** |
| 85 | * @param ms |
| 86 | * @returns |
| 87 | */ |
| 88 | async function sleep (ms) { |
| 89 | return new Promise(resolve => setTimeout(resolve, ms)) |
| 90 | } |
| 91 | |
| 92 | module.exports = { |
| 93 | generateRandomInteger, |
| 94 | generateRandomFloat, |
| 95 | generateRandomNumberArray, |
| 96 | generateRandomObject, |
| 97 | sleep, |
| 98 | secureRandom |
| 99 | } |