chore: randomizer cleanup (#2431)

src/internal/mersenne.ts

@@ -328,6 +328,7 @@ class MersenneTwister19937 {
 
 /**
  * Generates a MersenneTwister19937 randomizer with 32 bits of precision.
+ * This is the default randomizer used by Faker.
  *
  * @internal
  */

src/simple-faker.ts

@@ -77,7 +77,7 @@ export class SimpleFaker {
   }
 
   /** @internal */
-  private readonly _randomizer: Randomizer = generateMersenne32Randomizer();
+  private readonly _randomizer: Randomizer;
 
   readonly datatype: DatatypeModule = new DatatypeModule(this);
   readonly date: SimpleDateModule = new SimpleDateModule(this);

test/__snapshots__/mersenne.spec.ts.snap

@@ -1,13 +1,13 @@
 // Vitest Snapshot v1, https://vitest.dev/guide/snapshot.html
 
-exports[`mersenne twister > seed: [42,1,2] > should return deterministic value for next() 1`] = `0.8562037434894592`;
+exports[`generateMersenne32Randomizer() > seed: [42,1,2] > should return deterministic value for next() 1`] = `0.8562037434894592`;
 
-exports[`mersenne twister > seed: [1211,1,2] > should return deterministic value for next() 1`] = `0.8916433283593506`;
+exports[`generateMersenne32Randomizer() > seed: [1211,1,2] > should return deterministic value for next() 1`] = `0.8916433283593506`;
 
-exports[`mersenne twister > seed: [1337,1,2] > should return deterministic value for next() 1`] = `0.17990487208589911`;
+exports[`generateMersenne32Randomizer() > seed: [1337,1,2] > should return deterministic value for next() 1`] = `0.17990487208589911`;
 
-exports[`mersenne twister > seed: 42 > should return deterministic value for next() 1`] = `0.37454011430963874`;
+exports[`generateMersenne32Randomizer() > seed: 42 > should return deterministic value for next() 1`] = `0.37454011430963874`;
 
-exports[`mersenne twister > seed: 1211 > should return deterministic value for next() 1`] = `0.9285201537422836`;
+exports[`generateMersenne32Randomizer() > seed: 1211 > should return deterministic value for next() 1`] = `0.9285201537422836`;
 
-exports[`mersenne twister > seed: 1337 > should return deterministic value for next() 1`] = `0.2620246761944145`;
+exports[`generateMersenne32Randomizer() > seed: 1337 > should return deterministic value for next() 1`] = `0.2620246761944145`;

test/mersenne.spec.ts

@@ -6,9 +6,16 @@ import { times } from './support/times';
 
 const NON_SEEDED_BASED_RUN = 25;
 
-describe('mersenne twister', () => {
+describe('generateMersenne32Randomizer()', () => {
   const randomizer: Randomizer = generateMersenne32Randomizer();
 
+  it('should return a result matching the interface', () => {
+    expect(randomizer).toBeDefined();
+    expect(randomizer).toBeTypeOf('object');
+    expect(randomizer.next).toBeTypeOf('function');
+    expect(randomizer.seed).toBeTypeOf('function');
+  });
+
   describe.each(
     [...seededRuns, ...seededRuns.map((v) => [v, 1, 2])].map((v) => [v])
   )('seed: %j', (seed) => {