Add round type to toDecimal function (#57)

* add rounding type to toDecimal function * add unit test for roundint types
moonbeam-foundation · Feb 6, 2023 · 1942eaa · 1942eaa
1 parent 77664b2
commit 1942eaa
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Showing 2 changed files with 18 additions and 2 deletions.
diff --git a/packages/utils/src/numbers/decimals.test.ts b/packages/utils/src/numbers/decimals.test.ts
@@ -1,4 +1,5 @@
 /* eslint-disable jest/max-expects */
+import Big from 'big.js';
 import { toBigInt, toDecimal } from './decimals';
 
 describe('utils - decimals', () => {
@@ -42,6 +43,20 @@ describe('utils - decimals', () => {
       expect(toDecimal('711_158_793', 9, 9)).toBe(0.711158793);
       expect(toDecimal('711_158_793n', 9, 9)).toBe(0.711158793);
     });
+
+    it('should convert to decimals with the correct rounding types', () => {
+      expect(toDecimal(477_844_894, 9, 0)).toBe(0);
+      expect(toDecimal(370_024_965_982_774n, 12, 1, Big.roundDown)).toBe(370);
+      expect(toDecimal(477_844_894, 9, 0, Big.roundUp)).toBe(1);
+      expect(toDecimal('167_850_000n', 9, 4, Big.roundHalfEven)).toBe(0.1678);
+      expect(toDecimal('7_117_587_933_365_016_000', 18, 2)).toBe(7.12);
+      expect(toDecimal('7_117_587_933_365_016_000', 18, 2, Big.roundDown)).toBe(
+        7.11,
+      );
+      expect(
+        toDecimal('7_117_587_933_365_016_000', 18, 2, Big.roundHalfUp),
+      ).toBe(7.12);
+    });
   });
 
   describe('toBigInt', () => {

diff --git a/packages/utils/src/numbers/decimals.ts b/packages/utils/src/numbers/decimals.ts
@@ -1,13 +1,14 @@
-import Big from 'big.js';
+import Big, { RoundingMode } from 'big.js';
 
 export function toDecimal(
   number: bigint | number | string,
   decimals: number,
   maxDecimal = 6,
+  roundType?: RoundingMode,
 ): number {
   const dividend = Big(number.toString().replace(/[^0-9]/g, ''));
   const divisor = Big(10).pow(decimals);
-  const result = dividend.div(divisor).round(maxDecimal);
+  const result = dividend.div(divisor).round(maxDecimal, roundType);
 
   return result.toNumber();
 }