added new utility functions (#8)

Co-authored-by: Andrius Mozūraitis <andriusmozuraitis@thebankoflondon.com>

package.json

@@ -1,6 +1,6 @@
 {
   "name": "ts-prime",
-  "version": "1.0.1",
+  "version": "1.0.2",
   "description": "A utility library for JavaScript and Typescript.",
   "main": "dist/commonjs/index.js",
   "module": "dist/es/index.js",

src/randomItem.test.ts

@@ -0,0 +1,11 @@
+import { randomItemInArray } from './randomItem';
+
+describe('Random item test', () => {
+  test('Random item', () => {
+    expect(randomItemInArray([1, 2, 3, 4, 5], () => 0.1)).toEqual(1);
+    expect(randomItemInArray([1, 2, 3, 4, 5], () => 0.5123)).toEqual(3);
+    expect(randomItemInArray([1, 2, 3, 4, 5], () => 0.9123)).toEqual(5);
+    expect(randomItemInArray([1, 2, 3, 4, 5], () => 0.7642653)).toEqual(4);
+    return;
+  });
+});

src/randomItem.ts

@@ -0,0 +1,23 @@
+
+
+/**
+ * Return random number between two numbers
+ * 
+ * @param min - minimum
+ * @param max - maximum
+ * @param random - Random number generation function, by default function uses Math.random 
+ */
+export function randomIntFromInterval(min: number, max: number, random: () => number = Math.random) { // min and max included 
+  return Math.floor(random() * (max - min + 1) + min);
+}
+
+/**
+ * Picks random item in array
+ * 
+ * @param arr - Array to pick
+ * @param random - Random number generation function, by default function uses Math.random 
+ */
+export function randomItemInArray<T>(arr: T[], random: () => number = Math.random) {
+    const random_number = randomIntFromInterval(0, arr.length - 1, random)
+    return arr[random_number]
+}

src/slide.test.ts

@@ -0,0 +1,16 @@
+import { slide } from "./slide";
+
+test('slugify', () => {
+  expect(slide([1,2,3], 12)).toEqual(1);
+  expect(slide([1,2,3], 11)).toEqual(3);
+  expect(slide([1,2,3], 10)).toEqual(2);
+  expect(slide([1,2,3], 9)).toEqual(1);
+  expect(slide([1,2,3], 8)).toEqual(3);
+
+
+  expect(slide([1,2,3], 1.23)).toEqual(2);
+  expect(slide([1,2,3], 0.23)).toEqual(1);
+  expect(slide([1,2,3], 0.73)).toEqual(1);
+  expect(slide([1,2,3], 0.99)).toEqual(1);
+  expect(slide([1,2,3], 1.01)).toEqual(2);
+});

src/slide.ts

@@ -0,0 +1,34 @@
+import { purry } from "./purry";
+
+function _slide<T>(array: T[], count: number) {
+	if (array.length === 0) throw new TypeError("Can't accept empty arrays");
+	const size = array.length;
+	const divider = Math.floor(count) % size;
+	if (divider < 0) return array[size - divider];
+	return array[divider];
+}
+
+
+/**
+ * Slide through array with number
+ * @param items array to slide
+ * @example
+ *    slide([1,2,3,4,5], 0) // 1
+ *    slide([1,2,3,4,5], 1) // 2
+ *    slide([1,2,3,4,5], 10) // 5
+ *    slide([1,2,3,4,5], -1) // 5
+ *    slide([1,2,3,4,5], -2) // 4
+ *    slide([1,2,3,4,5], -2.34) // 4
+ *    slide([1,2,3,4,5], -4.3) // 2
+ * @signature
+ *    P.slugify(str);
+ * @example
+ *    P.slugify("Super ball cup") // => super-ball-cup
+ * @category Array
+ */
+export function slide<T>(items: readonly T[], count: number): T;
+export function slide<T>(count: number): (items: readonly T[]) => T;
+
+export function slide() {
+  return purry(_slide, arguments);
+}