Add randomFromObject function

lib/random.js

@@ -141,3 +141,14 @@ export function randomFromArray(array, rng = Math.random) {
   const index = randomInt(0, array.length, rng)
   return array[index]
 }
+
+/**
+ * Returns a random value from an object
+ * @template T
+ * @param {Record<string, T>} obj
+ * @param {Rng} rng 
+ * @returns {T}
+ */
+export function randomFromObject(obj, rng = Math.random) {
+  return obj[randomFromArray(Object.keys(obj), rng)]
+}

lib/random.test.js

@@ -0,0 +1,20 @@
+import assert from "node:assert"
+import { describe, it } from "node:test"
+import { randomFromObj } from './random.js'
+
+
+describe('randomFromObj', () => {
+  it('returns a value from the object', () => {
+    const obj = { a: 1, b: 2, c: 3 }
+    const rng = () => 0.5
+    assert.strictEqual(randomFromObj(obj, rng), 2)
+  })
+})
+
+describe('randomFromArray', () => {
+  it('returns a value from the object', () => {
+    const arr = [1,2,3]
+    const rng = () => 0.5
+    assert.strictEqual(randomFromArray(arr, rng), 2)
+  })
+})