feat(maths): add median fn

.changeset/cool-rice-compete.md

@@ -0,0 +1,5 @@
+---
+"@opentf/utils": minor
+---
+
+Added array, maths, types, object category utility fns.

README.md

@@ -43,13 +43,13 @@ bun add @opentf/utils
 ## Usage
 
 ```ts
-import { isNum, range, camelCase, sleep } from "@opentf/utils";
+import { isNum, range, pascalCase, sleep } from "@opentf/utils";
 
 isNum(NaN); //=> false
 
 range(1, 5); //=> [1, 2, 3, 4, 5]
 
-camelCase("i phone"); //=> 'iPhone'
+pascalCase("pascal case"); //=> PascalCase
 
 await sleep(1000); // It suspends the exection for 1 second.
 ```

packages/utils/__tests__/maths/median.spec.ts

@@ -0,0 +1,13 @@
+import { median } from '../../src';
+
+describe('Number', () => {
+  test('median', () => {
+    expect(median()).toBe(NaN);
+    expect(median([])).toBe(NaN);
+    expect(median([1])).toBe(1);
+    expect(median([4, 1, 7])).toBe(1);
+    expect(median([4, 2, 8])).toBe(2);
+    expect(median([1, 4, 2, 5, 0])).toBe(2);
+    expect(median([10, 20, 40, 50])).toBe(30);
+  });
+});

packages/utils/package.json

@@ -50,6 +50,7 @@
     "build": "tsup",
     "test": "jest",
     "test:w": "jest --watch",
+    "test:b": "bun test --watch",
     "lint": "eslint src/** --fix",
     "check-types": "tsc --noEmit",
     "ci": "turbo run build test lint check-types"

packages/utils/src/index.ts

@@ -24,6 +24,7 @@ export { default as odd } from './maths/odd';
 export { default as sum } from './maths/sum';
 export { default as prod } from './maths/prod';
 export { default as mean } from './maths/mean';
+export { default as median } from './maths/median';
 
 // Types
 export { default as isNum } from './types/isNum';

packages/utils/src/maths/median.ts

@@ -0,0 +1,26 @@
+import sort from '../array/sort';
+import even from './even';
+
+/**
+ * Calculates the median value of the given array.
+ *
+ * @example
+ *
+ * median([1, 4, 2, 5, 0]) //=> 2
+ *
+ * median([10, 20, 40, 50]) //=> 30;
+ */
+export default function median(
+  arr: number[] = [],
+  cb?: (val: number, index: number) => number
+) {
+  let a = cb ? arr.map(cb) : arr;
+  a = sort(arr);
+
+  if (even(a.length)) {
+    const i = a.length / 2;
+    return (arr[i] + arr[i - 1]) / 2;
+  }
+
+  return arr[Math.floor(a.length / 2)];
+}