decimaljs support

penumbra-zone · Nov 20, 2024 · 0dbb840 · 0dbb840
1 parent 39e67f5
commit 0dbb840
Show file tree

Hide file tree

Showing 5 changed files with 79 additions and 56 deletions.
diff --git a/.changeset/slow-cats-punch.md b/.changeset/slow-cats-punch.md
@@ -2,4 +2,4 @@
 '@penumbra-zone/types': patch
 ---
 
-Removing trailing zeroes from round func
+Round func updates: remove trailing zeros + exponent notation support
diff --git a/packages/types/package.json b/packages/types/package.json
@@ -36,6 +36,7 @@
   },
   "dependencies": {
     "bignumber.js": "^9.1.2",
+    "decimal.js": "^10.4.3",
     "idb": "^8.0.0",
     "lodash": "^4.17.21",
     "zod": "^3.23.8"

diff --git a/packages/types/src/round.test.ts b/packages/types/src/round.test.ts
@@ -7,7 +7,7 @@ describe('round function', () => {
     options: RoundOptions;
     expected: string;
   }[] = [
-    // Default rounding mode ('round')
+    // Default rounding mode ('half-up')
     {
       description: 'should round up using default rounding (round)',
       options: { value: 1.2345, decimals: 3 },
@@ -33,93 +33,109 @@ describe('round function', () => {
       options: { value: 5, decimals: 2 },
       expected: '5',
     },
-    // Rounding mode: 'ceil'
+    // Rounding mode: 'up'
     {
       description: 'should ceil to 2 decimals',
-      options: { value: 1.2345, decimals: 2, roundingMode: 'ceil' },
+      options: { value: 1.2345, decimals: 2, roundingMode: 'up' },
       expected: '1.24',
     },
     {
       description: 'should ceil a negative number',
-      options: { value: -1.2345, decimals: 2, roundingMode: 'ceil' },
-      expected: '-1.23',
+      options: { value: -1.2345, decimals: 2, roundingMode: 'up' },
+      expected: '-1.24',
     },
     {
       description: 'should ceil with zero decimals',
-      options: { value: 1.5, decimals: 0, roundingMode: 'ceil' },
+      options: { value: 1.5, decimals: 0, roundingMode: 'up' },
       expected: '2',
     },
-    // Rounding mode: 'floor'
+    // Rounding mode: 'down'
     {
       description: 'should floor to 2 decimals',
-      options: { value: 1.2399, decimals: 2, roundingMode: 'floor' },
+      options: { value: 1.2399, decimals: 2, roundingMode: 'down' },
       expected: '1.23',
     },
     {
       description: 'should floor a negative number',
-      options: { value: -1.2345, decimals: 2, roundingMode: 'floor' },
-      expected: '-1.24',
+      options: { value: -1.2345, decimals: 2, roundingMode: 'down' },
+      expected: '-1.23',
     },
     {
       description: 'should floor with zero decimals',
-      options: { value: 1.9, decimals: 0, roundingMode: 'floor' },
+      options: { value: 1.9, decimals: 0, roundingMode: 'down' },
       expected: '1',
     },
-    // Edge Cases
+    // Exponential Notation Test Cases
     {
-      description: 'should handle large numbers',
-      options: { value: 1.23456789e10, decimals: 4, roundingMode: 'round' },
-      expected: '12345678900',
+      description: 'should handle extremely large numbers with round mode',
+      options: { value: 5.770789431026099e23, decimals: 4, roundingMode: 'half-up' },
+      expected: '5.7708e+23',
     },
     {
-      description: 'should handle extremely large numbers',
-      options: { value: 5.770789431026099e23, decimals: 4, roundingMode: 'round' },
+      description: 'should handle extremely large numbers with floor mode',
+      options: { value: 5.770789431026099e23, decimals: 4, roundingMode: 'down' },
+      expected: '5.7707e+23',
+    },
+    {
+      description: 'should handle extremely large numbers with ceil mode',
+      options: { value: 5.770789431026099e23, decimals: 4, roundingMode: 'up' },
       expected: '5.7708e+23',
     },
+    {
+      description: 'should handle extremely large negative numbers',
+      options: { value: -5.770789431026099e23, decimals: 4, roundingMode: 'half-up' },
+      expected: '-5.7708e+23',
+    },
+    // Edge Cases
+    {
+      description: 'should handle large numbers',
+      options: { value: 1.23456789e10, decimals: 4, roundingMode: 'half-up' },
+      expected: '12345678900',
+    },
     {
       description: 'should remove trailing zeros',
-      options: { value: 1.0000000001, decimals: 4, roundingMode: 'round' },
+      options: { value: 1.0000000001, decimals: 4, roundingMode: 'half-up' },
       expected: '1',
     },
     {
       description: 'should handle very small numbers',
-      options: { value: 0.000123456, decimals: 8, roundingMode: 'round' },
+      options: { value: 0.000123456, decimals: 8, roundingMode: 'half-up' },
       expected: '0.00012346',
     },
     {
       description: 'should handle Infinity',
-      options: { value: Infinity, decimals: 2, roundingMode: 'round' },
+      options: { value: Infinity, decimals: 2, roundingMode: 'half-up' },
       expected: 'Infinity',
     },
     {
       description: 'should handle -Infinity',
-      options: { value: -Infinity, decimals: 2, roundingMode: 'floor' },
+      options: { value: -Infinity, decimals: 2, roundingMode: 'down' },
       expected: '-Infinity',
     },
     {
       description: 'should handle NaN',
-      options: { value: NaN, decimals: 2, roundingMode: 'ceil' },
+      options: { value: NaN, decimals: 2, roundingMode: 'up' },
       expected: 'NaN',
     },
     {
       description: 'should handle decimals greater than available decimal places',
-      options: { value: 1.2, decimals: 5, roundingMode: 'floor' },
+      options: { value: 1.2, decimals: 5, roundingMode: 'down' },
       expected: '1.2',
     },
     // Rounding to integer
     {
       description: 'should round to integer using round mode',
-      options: { value: 2.5, decimals: 0, roundingMode: 'round' },
+      options: { value: 2.5, decimals: 0, roundingMode: 'half-up' },
       expected: '3',
     },
     {
       description: 'should ceil to integer',
-      options: { value: 2.1, decimals: 0, roundingMode: 'ceil' },
+      options: { value: 2.1, decimals: 0, roundingMode: 'up' },
       expected: '3',
     },
     {
       description: 'should floor to integer',
-      options: { value: 2.9, decimals: 0, roundingMode: 'floor' },
+      options: { value: 2.9, decimals: 0, roundingMode: 'down' },
       expected: '2',
     },
   ];

diff --git a/packages/types/src/round.ts b/packages/types/src/round.ts
@@ -1,53 +1,56 @@
-import { ceil as lodashCeil, floor as lodashFloor, round as lodashRound } from 'lodash';
+import { Decimal } from 'decimal.js';
 import { removeTrailingZeros } from './shortify.js';
 
-export type RoundingMode = 'round' | 'ceil' | 'floor';
+export type RoundingMode = 'half-up' | 'up' | 'down';
 
 export interface RoundOptions {
   value: number;
   decimals: number;
   roundingMode?: RoundingMode;
 }
 
-const roundingStrategies = {
-  ceil: lodashCeil,
-  floor: lodashFloor,
-  round: lodashRound,
-} as const;
+const EXPONENTIAL_NOTATION_THRESHOLD = new Decimal('1e21');
 
-const EXPONENTIAL_NOTATION_THRESHOLD = 1e21;
+Decimal.set({ precision: 30 });
+
+const getDecimalRoundingMode = (mode: RoundingMode): Decimal.Rounding => {
+  switch (mode) {
+    case 'up':
+      return Decimal.ROUND_UP;
+    case 'down':
+      return Decimal.ROUND_DOWN;
+    case 'half-up':
+    default:
+      return Decimal.ROUND_HALF_UP;
+  }
+};
 
 /**
- * Rounds a number based on the specified options.
- *
  * @param options - An object containing the properties:
  *   - value: The number to round.
  *   - decimals: The number of decimal places to round to.
- *   - roundingMode: The mode of rounding ('round', 'ceil', 'floor'). Defaults to 'round'.
- *
- * @returns A string representation of the rounded number.
- *
- * @example
- *
- * ```typescript
- * round({ value: 1.2345, decimals: 2, roundingMode: 'ceil' }); // "1.24"
- * round({ value: 1.2345, decimals: 2, roundingMode: 'floor' }); // "1.23"
- * round({ value: 1.2345, decimals: 2 }); // "1.23" (default rounding)
- * ```
+ *   - roundingMode:
+ *      - half-up: Default. Rounds towards nearest neighbour. If equidistant, rounds away from zero.
+ *      - down: Rounds towards zero
+ *      - up: Rounds way from zero
  */
-export function round({ value, decimals, roundingMode = 'round' }: RoundOptions): string {
-  const roundingFn = roundingStrategies[roundingMode];
-  const roundedNumber = roundingFn(value, decimals);
+export function round({ value, decimals, roundingMode = 'half-up' }: RoundOptions): string {
+  const decimalValue = new Decimal(value);
 
-  let result: string;
+  // Determine if exponential notation is needed
+  const isLargeNumber = decimalValue.abs().gte(EXPONENTIAL_NOTATION_THRESHOLD);
+  const isSmallNumber = decimalValue.abs().lt(new Decimal('1e-4')) && !decimalValue.isZero();
 
-  const isLargeNumber = Math.abs(roundedNumber) >= EXPONENTIAL_NOTATION_THRESHOLD;
-  const isSmallNumber = Math.abs(roundedNumber) < 1e-4 && roundedNumber !== 0;
+  let result: string;
 
   if (isLargeNumber || isSmallNumber) {
-    result = roundedNumber.toExponential(decimals);
+    result = decimalValue.toExponential(decimals, getDecimalRoundingMode(roundingMode));
   } else {
-    result = roundedNumber.toFixed(decimals);
+    const roundedDecimal = decimalValue.toDecimalPlaces(
+      decimals,
+      getDecimalRoundingMode(roundingMode),
+    );
+    result = roundedDecimal.toFixed(decimals, getDecimalRoundingMode(roundingMode));
   }
 
   return removeTrailingZeros(result);

diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml