add number utilities

package.json

@@ -1,7 +1,7 @@
 {
   "name": "@curiousleaf/utils",
   "description": "A lightweight set of utilities",
-  "version": "1.0.26",
+  "version": "1.0.27",
   "license": "MIT",
   "type": "module",
   "author": {
@@ -15,7 +15,7 @@
   "scripts": {
     "build": "bun build ./src/index.ts --outdir ./dist && bun run build:declaration",
     "build:declaration": "tsc --emitDeclarationOnly",
-    "lint": "bun biome lint .",
+    "lint": "bun biome lint --apply .",
     "format": "bun biome format --write ."
   },
   "dependencies": {

src/helpers/helpers.ts

@@ -175,11 +175,11 @@ export const setInputValue = (
 ) => {
   const nativeInputValueSetter = Object.getOwnPropertyDescriptor(
     HTMLInputElement.prototype,
-    'value',
+    "value",
   )?.set
 
   nativeInputValueSetter?.call(input, value)
 
   // Trigger a change event if the value was changed
-  triggerChange && input?.dispatchEvent(new Event('input', { bubbles: true }))
+  triggerChange && input?.dispatchEvent(new Event("input", { bubbles: true }))
 }

src/numbers/numbers.test.ts

@@ -1,6 +1,6 @@
 import { describe, expect, it } from "bun:test"
 
-import { keepNumberInRange, parseNumericValue } from "./numbers"
+import { keepNumberInRange, parseNumericValue, preciseRound } from "./numbers"
 
 describe("keepNumberInRange", () => {
   it("returns the same value if no range is specified", () => {
@@ -34,6 +34,32 @@ describe("parseNumericValue", () => {
   })
 
   it("returns the original string if it cannot be parsed", () => {
-    expect(parseNumericValue("not a number")).toBe("not a number")
+    expect(parseNumericValue("not a number")).toBe(undefined)
+  })
+})
+
+describe("preciseRound", () => {
+  it("rounds to 2 decimal places by default", () => {
+    expect(preciseRound(2.345)).toEqual(2.35)
+  })
+
+  it("rounds to specified decimal places", () => {
+    expect(preciseRound(2.34567, 3)).toEqual(2.346)
+  })
+
+  it("handles rounding up at 0.5 exactly", () => {
+    expect(preciseRound(2.005, 2)).toEqual(2.01)
+  })
+
+  it("handles negative numbers", () => {
+    expect(preciseRound(-2.345)).toEqual(-2.34)
+  })
+
+  it("rounds to 0 decimal places correctly", () => {
+    expect(preciseRound(2.5, 0)).toEqual(3)
+  })
+
+  it("trims the number of decimal places if the value is an integer", () => {
+    expect(preciseRound(2.0000003, 2)).toEqual(2)
   })
 })

src/numbers/numbers.ts

@@ -25,11 +25,24 @@ export const keepNumberInRange = (value: number, min?: number, max?: number) =>
 
 /**
  * Parse a string into a numeric value.
- * @param string - The string to parse.
- * @returns The parsed numeric value, or the original string if it cannot be parsed.
+ * @param value - The value to parse into a numeric value.
+ * @returns The parsed numeric value, or `undefined` if the value cannot be parsed.
  */
-export const parseNumericValue = (string: string) => {
-  const number = Number.parseFloat(string)
+export const parseNumericValue = (value?: string | number | null) => {
+  if (value === undefined || value === null) return undefined
+  const parsed = Number.parseFloat(value.toString())
 
-  return Number.isNaN(number) ? string : number
+  return Number.isNaN(parsed) ? undefined : parsed
+}
+
+/**
+ * Rounds a number to a specified number of decimal places, with an adjustment for floating point precision.
+ * @param value - The number to round.
+ * @param decimals - The number of decimal places to round to. Defaults to 2.
+ * @returns The rounded number.
+ */
+export const preciseRound = (value: number, decimals = 2) => {
+  const factor = Math.pow(10, decimals)
+
+  return Math.round((value + Number.EPSILON) * factor) / factor
 }