fix(uint32ArrayFrom): increment index & polyfill for Uint32Array (#270)

increment index and polyfill for Uint32Array instead of Array

Author: texastony

packages/util/src/uint32ArrayFrom.ts

@@ -3,11 +3,12 @@
 
 // IE 11 does not support Array.from, so we do it manually
 export function uint32ArrayFrom(a_lookUpTable: Array<number>): Uint32Array {
-  if (!Array.from) {
+  if (!Uint32Array.from) {
     const return_array = new Uint32Array(a_lookUpTable.length)
     let a_index = 0
     while (a_index < a_lookUpTable.length) {
       return_array[a_index] = a_lookUpTable[a_index]
+      a_index += 1
     }
     return return_array
   }

packages/util/test/uint32ArrayFrom.test.ts

@@ -0,0 +1,20 @@
+// Copyright Amazon.com Inc. or its affiliates. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+import { expect } from "chai";
+import "mocha";
+import { uint32ArrayFrom } from "../src/uint32ArrayFrom";
+
+describe("uint32ArrayFrom", () =>{
+  it("When given an empty array, should return an empty array", () => {
+    expect(uint32ArrayFrom(Array.of(0)))
+      .to
+      .eql(Uint32Array.of(0))
+  })
+
+  it("Given a populated array, returns a valid Uint32 Array", () => {
+    expect(uint32ArrayFrom(Array.of(0x00000000, 0xF26B8303, 0xE13B70F7)))
+      .to
+      .eql(Uint32Array.of(0, 4067132163, 3778769143))
+  })
+})