Update version to 4.7.0, add countDecimalPlaces function for counting decimal places in numbers, and document changes in CHANGELOG.md and README.md. Include tests for countDecimalPlaces functionality.

Author: ogroppo

CHANGELOG.md

@@ -1,5 +1,11 @@
 # deverything
 
+## 4.7.0
+
+### Minor Changes
+
+- countDecimalPlaces
+
 ## 4.6.0
 
 ### Minor Changes

README.md

@@ -77,6 +77,7 @@ Contributions always welcome!
 ### Math
 
 - `average()`
+- `countDecimalPlaces()` count the number of decimal places in a number
 - `isBetween()`
 - `isOutside()`
 - `isStrictlyBetween()`

package.json

@@ -1,6 +1,6 @@
 {
   "name": "deverything",
-  "version": "4.6.0",
+  "version": "4.7.0",
   "description": "Everything you need for Dev",
   "main": "./dist/index.js",
   "module": "./dist/index.mjs",

src/math/countDecimalPlaces.test.ts

@@ -0,0 +1,37 @@
+import { describe, expect, test } from "vitest";
+import { countDecimalPlaces } from "./countDecimalPlaces";
+
+describe("countDecimalPlaces", () => {
+  test("integers", () => {
+    expect(countDecimalPlaces(0)).toBe(0);
+    expect(countDecimalPlaces(1)).toBe(0);
+    expect(countDecimalPlaces(100)).toBe(0);
+    expect(countDecimalPlaces(-5)).toBe(0);
+  });
+
+  test("decimals", () => {
+    expect(countDecimalPlaces(1.5)).toBe(1);
+    expect(countDecimalPlaces(1.23)).toBe(2);
+    expect(countDecimalPlaces(1.234567)).toBe(6);
+    expect(countDecimalPlaces(0.1)).toBe(1);
+    expect(countDecimalPlaces(0.123456789)).toBe(9);
+  });
+
+  test("negative decimals", () => {
+    expect(countDecimalPlaces(-1.5)).toBe(1);
+    expect(countDecimalPlaces(-1.23)).toBe(2);
+    expect(countDecimalPlaces(-0.123)).toBe(3);
+  });
+
+  test("scientific notation", () => {
+    expect(countDecimalPlaces(1e-5)).toBe(5);
+    expect(countDecimalPlaces(1.23e-2)).toBe(4);
+    expect(countDecimalPlaces(1.5e2)).toBe(0);
+  });
+
+  test("edge cases", () => {
+    expect(countDecimalPlaces(Infinity)).toBe(0);
+    expect(countDecimalPlaces(-Infinity)).toBe(0);
+    expect(countDecimalPlaces(NaN)).toBe(0);
+  });
+});

src/math/countDecimalPlaces.ts

@@ -0,0 +1,27 @@
+/**
+ * Counts the number of decimal places in a number.
+ * @example
+ * countDecimalPlaces(1.23); // 2
+ * countDecimalPlaces(1.234567); // 6
+ * countDecimalPlaces(5); // 0
+ * countDecimalPlaces(0.1); // 1
+ */
+export const countDecimalPlaces = (num: number): number => {
+  if (!Number.isFinite(num)) return 0;
+
+  const numStr = num.toString();
+
+  // Handle scientific notation
+  if (numStr.includes("e")) {
+    const [, exponent] = numStr.split("e");
+    const exp = parseInt(exponent, 10);
+    const [base] = numStr.split("e");
+    const basePlaces = base.includes(".") ? base.split(".")[1].length : 0;
+    return Math.max(0, basePlaces - exp);
+  }
+
+  // Handle regular decimal notation
+  if (!numStr.includes(".")) return 0;
+
+  return numStr.split(".")[1].length;
+};

src/math/index.ts

@@ -1,4 +1,5 @@
 export * from "./average";
+export * from "./countDecimalPlaces";
 export * from "./isBetween";
 export * from "./isOutside";
 export * from "./isStrictlyBetween";