⚡️ Faster generation of ulid (#4092)

Author: dubzzz

.yarn/versions/d7649f72.yml

@@ -0,0 +1,8 @@
+releases:
+  fast-check: minor
+
+declined:
+  - "@fast-check/ava"
+  - "@fast-check/jest"
+  - "@fast-check/vitest"
+  - "@fast-check/worker"

packages/fast-check/src/arbitrary/_internals/mappers/UintToBase32String.ts

@@ -60,11 +60,6 @@ const decodeSymbolLookupTable: Record<string, number> = {
   Z: 31,
 };
 
-/** @internal */
-function getBaseLog(x: number, y: number) {
-  return Math.log(y) / Math.log(x);
-}
-
 /** @internal */
 function encodeSymbol(symbol: number) {
   return symbol < 10 ? String(symbol) : encodeSymbolLookupTable[symbol];
@@ -81,20 +76,11 @@ function pad(value: string, paddingLength: number) {
 
 /** @internal */
 export function uintToBase32StringMapper(num: number, paddingLength: number): string {
-  if (num === 0) {
-    return pad('0', paddingLength);
-  }
-
   let base32Str = '';
-  let remaining = num;
-  for (let symbolsLeft = Math.floor(getBaseLog(32, num)) + 1; symbolsLeft > 0; symbolsLeft--) {
-    const val = Math.pow(32, symbolsLeft - 1);
-    const symbol = Math.floor(remaining / val);
-
-    base32Str += encodeSymbol(symbol);
-    remaining -= symbol * val;
+  for (let remaining = num; remaining !== 0; remaining = Math.floor(remaining / 32)) {
+    const current = remaining % 32;
+    base32Str = encodeSymbol(current) + base32Str;
   }
-
   return pad(base32Str, paddingLength);
 }
 

packages/fast-check/test/unit/arbitrary/_internals/mappers/UintToBase32String.spec.ts

@@ -7,9 +7,9 @@ import {
 describe('uintToBase32StringUnmapper', () => {
   it('should be able to unmap any mapped value', () =>
     fc.assert(
-      fc.property(fc.integer({ min: 0 }), (input) => {
+      fc.property(fc.maxSafeNat(), (input) => {
         // Arrange
-        const mapped = paddedUintToBase32StringMapper(10)(input);
+        const mapped = paddedUintToBase32StringMapper(12)(input);
         // Act
         const out = uintToBase32StringUnmapper(mapped);
         // Assert