Maybe enough for a CJS build?

Still seem to be issues for the integration I'm testing.
One to pick up with more motivation in the New Year!

lib/usb-partial-flashing.ts

@@ -55,9 +55,13 @@ import {
   pageAlignBlocks,
   read32FromUInt8Array,
 } from "./usb-partial-flashing-utils.js";
-import MemoryMap from "nrf-intel-hex";
 import { BoardVersion } from "./device.js";
 
+// Workaround for packaging issues
+import * as Hex from "nrf-intel-hex";
+const MemoryMapClass = (Hex.default as any).default ?? Hex.default;
+type MemoryMap = Hex.default;
+
 type ProgressCallback = (n: number, partial: boolean) => void;
 
 // Source code for binaries in can be found at https://github.com/microsoft/pxt-microbit/blob/dec5b8ce72d5c2b4b0b20aafefce7474a6f0c7b2/external/sha/source/main.c
@@ -205,7 +209,7 @@ export class PartialFlashing {
   // Falls back to a full flash if partial flashing fails.
   // Drawn from https://github.com/microsoft/pxt-microbit/blob/dec5b8ce72d5c2b4b0b20aafefce7474a6f0c7b2/editor/extension.tsx#L335
   private async partialFlashAsync(
-    data: string | Uint8Array | MemoryMap.default,
+    data: string | Uint8Array | MemoryMap,
     updateProgress: ProgressCallback,
   ): Promise<boolean> {
     const flashBytes = this.convertDataToPaddedBytes(data);
@@ -251,7 +255,7 @@ export class PartialFlashing {
 
   // Perform full flash of micro:bit's ROM using daplink.
   async fullFlashAsync(
-    data: string | Uint8Array | MemoryMap.default,
+    data: string | Uint8Array | MemoryMap,
     updateProgress: ProgressCallback,
   ) {
     this.log("Full flash");
@@ -279,7 +283,7 @@ export class PartialFlashing {
   // Flash the micro:bit's ROM with the provided image, resetting the micro:bit first.
   // Drawn from https://github.com/microsoft/pxt-microbit/blob/dec5b8ce72d5c2b4b0b20aafefce7474a6f0c7b2/editor/extension.tsx#L439
   async flashAsync(
-    data: string | Uint8Array | MemoryMap.default,
+    data: string | Uint8Array | MemoryMap,
     updateProgress: ProgressCallback,
   ): Promise<boolean> {
     let resetPromise = (async () => {
@@ -321,7 +325,7 @@ export class PartialFlashing {
   }
 
   private convertDataToHexString(
-    data: string | Uint8Array | MemoryMap.default,
+    data: string | Uint8Array | MemoryMap,
   ): string {
     if (typeof data === "string") {
       return data;
@@ -333,7 +337,7 @@ export class PartialFlashing {
   }
 
   private convertDataToPaddedBytes(
-    data: string | Uint8Array | MemoryMap.default,
+    data: string | Uint8Array | MemoryMap,
   ): Uint8Array {
     if (data instanceof Uint8Array) {
       return data;
@@ -345,26 +349,15 @@ export class PartialFlashing {
   }
 
   private hexStringToPaddedBytes(hex: string): Uint8Array {
-    // Cludge for a packaging issue
-    const fromHex: (
-      hexText: string,
-      maxBlockSize?: number,
-    ) => MemoryMap.default =
-      (MemoryMap as any).fromHex ?? MemoryMap.default.fromHex;
-
-    return this.memoryMapToPaddedBytes(fromHex(hex));
+    const m = MemoryMapClass.fromHex(hex);
+    return this.memoryMapToPaddedBytes(m);
   }
 
   private paddedBytesToHexString(data: Uint8Array): string {
-    // Cludge for a packaging issue
-    const fromPaddedUint8Array: (data: Uint8Array) => MemoryMap.default =
-      (MemoryMap as any).fromPaddedUint8Array ??
-      MemoryMap.default.fromPaddedUint8Array;
-
-    return fromPaddedUint8Array(data).asHexString();
+    return MemoryMapClass.fromPaddedUint8Array(data).asHexString();
   }
 
-  private memoryMapToPaddedBytes(memoryMap: MemoryMap.default): Uint8Array {
+  private memoryMapToPaddedBytes(memoryMap: MemoryMap): Uint8Array {
     const flashSize = {
       V1: 256 * 1024,
       V2: 512 * 1024,

package.json

@@ -2,15 +2,21 @@
   "name": "@microbit/microbit-connection",
   "version": "0.0.0",
   "type": "module",
-  "module": "./build/index.js",
+  "main": "./build/cjs/index.js",
+  "module": "./build/esm/index.js",
+  "types": "./build/esm/index.d.ts",
   "exports": {
     ".": {
-      "import": "./build/index.js"
+      "import": "./build/esm/index.js",
+      "require": "./build/cjs/index.js",
+      "types": "./build/esm/index.d.ts"
     }
   },
   "scripts": {
     "dev": "vite",
-    "build:lib": "tsc",
+    "build:esm": "tsc -p tsconfig.json",
+    "build:cjs": "tsc -p tsconfig.cjs.json",
+    "build:lib": "npm run build:esm && npm run build:cjs",
     "build:demo": "vite build --mode=demo",
     "ci": "npm run build:lib && npm run test && npx prettier --check lib src",
     "test": "vitest",

tsconfig.cjs.json

@@ -0,0 +1,8 @@
+{
+  "extends": "./tsconfig.json",
+  "compilerOptions": {
+    "module": "CommonJS",
+    "moduleResolution": "Node",
+    "outDir": "./build/cjs"
+  }
+}

tsconfig.json

@@ -8,10 +8,9 @@
 
     /* Bundler mode */
     "moduleResolution": "NodeNext",
-    "resolveJsonModule": true,
     "isolatedModules": true,
     "moduleDetection": "force",
-    "outDir": "build",
+    "outDir": "build/esm",
     "sourceMap": true,
     "declaration": true,