# How to use unsafeNext method in fast-check-monorepo

Best JavaScript code snippet using fast-check-monorepo

LinearCongruential.ts

Source:LinearCongruential.ts

`...30 return new LinearCongruential(this.seed);31 }32 next(): [number, LinearCongruential] {33 const nextRng = new LinearCongruential(this.seed);34 const out = nextRng.unsafeNext();35 return [out, nextRng];36 }37 unsafeNext(): number {38 this.seed = computeNextSeed(this.seed);39 return computeValueFromNextSeed(this.seed);40 }41}42class LinearCongruential32 implements RandomGenerator {43 static readonly min: number = 0;44 static readonly max: number = 0xffffffff;45 constructor(private seed: number) {}46 min(): number {47 return LinearCongruential32.min;48 }49 max(): number {50 return LinearCongruential32.max;51 }52 clone(): LinearCongruential32 {53 return new LinearCongruential32(this.seed);54 }55 next(): [number, LinearCongruential32] {56 const nextRng = new LinearCongruential32(this.seed);57 const out = nextRng.unsafeNext();58 return [out, nextRng];59 }60 unsafeNext(): number {61 const s1 = computeNextSeed(this.seed);62 const v1 = computeValueFromNextSeed(s1);63 const s2 = computeNextSeed(s1);64 const v2 = computeValueFromNextSeed(s2);65 this.seed = computeNextSeed(s2);66 const v3 = computeValueFromNextSeed(this.seed);67 // value between: -0x80000000 and 0x7fffffff68 // in theory it should have been: v1 & 3 instead of v1 alone69 // but as binary operations truncate between -0x80000000 and 0x7fffffff in JavaScript70 // we can get rid of this operation71 const vnext = v3 + ((v2 + (v1 << 15)) << 15);72 return ((vnext + 0x80000000) | 0) + 0x80000000;73 }74}...`

LinearCongruencial.spec.ts

Source:LinearCongruencial.spec.ts

`1import * as assert from 'assert';2import * as fc from 'fast-check';3import { congruential, congruential32 } from '../../../src/generator/LinearCongruential';4import { uniformIntDistribution } from '../../../src/distribution/UniformIntDistribution';5import * as p from './RandomGenerator.properties';6describe('congruential', () => {7 it('Should produce the right sequence for seed=42', () => {8 let g = congruential(42);9 let data = [];10 for (let idx = 0; idx !== 10; ++idx) {11 const [v, nextG] = g.next();12 data.push(v);13 g = nextG;14 }15 // Same values as Visual C++ rand() for srand(42)16 assert.deepEqual(data, [175, 400, 17869, 30056, 16083, 12879, 8016, 7644, 15809, 1769]);17 });18 it('Should return the same sequence given same seeds', () => fc.assert(p.sameSeedSameSequences(congruential)));19 it('Should return the same sequence if called twice', () => fc.assert(p.sameSequencesIfCallTwice(congruential)));20 it('Should generate values between 0 and 2**15 -1', () => fc.assert(p.valuesInRange(congruential)));21 it('Should impact itself with unsafeNext', () => fc.assert(p.changeSelfWithUnsafeNext(congruential)));22 it('Should not impact itself with next', () => fc.assert(p.noChangeSelfWithNext(congruential)));23 it('Should not impact clones when impacting itself on unsafeNext', () =>24 fc.assert(p.noChangeOnClonedWithUnsafeNext(congruential)));25});26describe('congruential32', () => {27 it('Should return the same sequence given same seeds', () => fc.assert(p.sameSeedSameSequences(congruential32)));28 it('Should return the same sequence if called twice', () => fc.assert(p.sameSequencesIfCallTwice(congruential32)));29 it('Should generate values between 0 and 2**32 -1', () => fc.assert(p.valuesInRange(congruential32)));30 it('Should be equivalent to a uniform distribution of congruential over 32 bits', () =>31 fc.assert(32 fc.property(fc.integer(), fc.integer({ min: 1, max: 100 }), (seed, num) => {33 let rng = congruential(seed);34 let rng32 = congruential32(seed);35 const dist = uniformIntDistribution(0, 0xffffffff);36 for (let idx = 0; idx !== num; ++idx) {37 const [v1, nrng] = dist(rng);38 const [v2, nrng32] = dist(rng32);39 if (v1 !== v2) {40 return false;41 }42 rng = nrng;43 rng32 = nrng32;44 }45 return true;46 })47 ));48 it('Should impact itself with unsafeNext', () => fc.assert(p.changeSelfWithUnsafeNext(congruential32)));49 it('Should not impact itself with next', () => fc.assert(p.noChangeSelfWithNext(congruential32)));50 it('Should not impact clones when impacting itself on unsafeNext', () =>51 fc.assert(p.noChangeOnClonedWithUnsafeNext(congruential32)));...`

RandomGenerator.ts

Source:RandomGenerator.ts

`...9 next(): [number, RandomGenerator];10 /** Compute the jumped generator (does not impact current instance) */11 jump?(): RandomGenerator;12 /** Generate next value BUT alters current generator */13 unsafeNext(): number;14 /** Jump current generator */15 unsafeJump?(): void;16}17export function unsafeGenerateN(rng: RandomGenerator, num: number): number[] {18 const out: number[] = [];19 for (let idx = 0; idx != num; ++idx) {20 out.push(rng.unsafeNext());21 }22 return out;23}24export function generateN(rng: RandomGenerator, num: number): [number[], RandomGenerator] {25 const nextRng = rng.clone();26 const out = unsafeGenerateN(nextRng, num);27 return [out, nextRng];28}29export function unsafeSkipN(rng: RandomGenerator, num: number): void {30 for (let idx = 0; idx != num; ++idx) {31 rng.unsafeNext();32 }33}34export function skipN(rng: RandomGenerator, num: number): RandomGenerator {35 const nextRng = rng.clone();36 unsafeSkipN(nextRng, num);37 return nextRng;...`

Using AI Code Generation

`1const { unsafeNext } = require('fast-check');2const { unsafeNext } = require('fast-check');3const { unsafeNext } = require('fast-check');4const { unsafeNext } = require('fast-check');5const { unsafeNext } = require('fast-check');6const { unsafeNext } = require('fast-check');7const { unsafeNext } = require('fast-check');8const { unsafeNext } = require('fast-check');9const { unsafeNext } = require('fast-check');10const { unsafeNext } = require('fast-check');11const { unsafeNext } = require('fast-check');12const { unsafeNext } = require('fast-check');13const { unsafeNext } = require('fast-check');14const { unsafeNext } = require('fast-check');15const { unsafeNext } = require('fast-check');16const { unsafeNext } = require('fast-check');17const { unsafeNext } = require('fast-check');18const { unsafeNext } = require('fast-check');`

Using AI Code Generation

`1const fc = require("fast-check");2const { unsafeNext } = require("fast-check/lib/check/arbitrary/definition/UnsafeNextArbitrary.js");3const { generate } = require("fast-check/lib/check/arbitrary/definition/NextArbitrary.js");4const { Random } = require("fast-check/lib/random/generator/Random.js");5const { seed } = require("fast-check/lib/random/RandomSeed.js");6const { Stream } = require("fast-check/lib/stream/Stream.js");7const { stream } = require("fast-check/lib/stream/Stream.js");8const unsafeNextArbitrary = unsafeNext(fc.anything(), 0);9const nextArbitrary = generate(unsafeNextArbitrary, 0);10const random = new Random(seed(0));11const streamOfRandoms = Stream.fromArray([random, random, random]);12const streamOfNexts = streamOfRandoms.map(random => nextArbitrary.generate(random));13const streamOfUnsafeNexts = streamOfNexts.map(next => unsafeNextArbitrary.canonicalFrom(next.value));14const streamOfValues = streamOfUnsafeNexts.map(unsafeNext => unsafeNext.value);15streamOfValues.forEach(value => console.log(value));16const fc = require("fast-check");17const { unsafeNext } = require("fast-check/lib/check/arbitrary/definition/UnsafeNextArbitrary.js");18const { generate } = require("fast-check/lib/check/arbitrary/definition/NextArbitrary.js");19const { Random } = require("fast-check/lib/random/generator/Random.js");20const { seed } = require("fast-check/lib/random/RandomSeed.js");21const { Stream } = require("fast-check/lib/stream/Stream.js");22const { stream } = require("fast-check/lib/stream/Stream.js");23const unsafeNextArbitrary = unsafeNext(fc.anything(), 0);24const nextArbitrary = generate(unsafeNextArbitrary, 1);25const random = new Random(seed`

Using AI Code Generation

`1const fc = require("fast-check");2const arb = fc.integer(0, 100);3const arb2 = fc.integer(0, 100);4const arb3 = fc.tuple(arb, arb2);5const arb4 = fc.nat();6const arb5 = fc.nat();7const arb6 = fc.tuple(arb4, arb5);8const arb7 = fc.tuple(arb6, arb3);9const arb8 = fc.tuple(arb7, arb6);10const arb9 = fc.tuple(arb8, arb7);11const arb10 = fc.tuple(arb9, arb8);12const arb11 = fc.tuple(arb10, arb9);13const arb12 = fc.tuple(arb11, arb10);14const arb13 = fc.tuple(arb12, arb11);15const arb14 = fc.tuple(arb13, arb12);16const arb15 = fc.tuple(arb14, arb13);17const arb16 = fc.tuple(arb15, arb14);18const arb17 = fc.tuple(arb16, arb15);19const arb18 = fc.tuple(arb17, arb16);20const arb19 = fc.tuple(arb18, arb17);21const arb20 = fc.tuple(arb19, arb18);22fc.assert(23fc.property(arb20, (x) => {24console.log(x);25return true;26})27);`

Using AI Code Generation

`1const fc = require("fast-check");2const vals = [];3for (let i = 0; i < 100; i++) {4 vals.push(fc.unsafeNext(fc.array(fc.integer())).value);5}6console.log(vals);7const fc = require("fast-check");8const vals = [];9for (let i = 0; i < 100; i++) {10 vals.push(fc.unsafeNext(fc.array(fc.integer())).value);11}12console.log(vals);`

Using AI Code Generation

`1const fc = require('fast-check');2const unsafeNext = require('fast-check/lib/arbitrary/definition/UnsafeNextArbitrary.js').unsafeNext;3const safeNext = (arbitrary) => {4 const arb = arbitrary.generate(0);5 return unsafeNext(arb);6}7const safeArb = fc.array(fc.integer(), 1, 1)8 .map(arr => arr[0]);9const unsafeArb = fc.array(fc.integer(), 1, 1)10 .map(arr => arr[0])11 .map(unsafeNext);`

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