Omit HID libraries for hardware-wallets package on unsupported enviro…

…nments (#798).

packages/hardware-wallets/package.json

@@ -15,7 +15,6 @@
   "dependencies": {
     "@ledgerhq/hw-app-eth": "5.3.0",
     "@ledgerhq/hw-transport": "5.3.0",
-    "@ledgerhq/hw-transport-node-hid": "5.3.0",
     "@ledgerhq/hw-transport-u2f": "5.3.0",
     "ethers": ">=5.0.0-beta.166"
   },
@@ -33,6 +32,9 @@
   "main": "./lib/index.js",
   "module": "./lib.esm/index.js",
   "name": "@ethersproject/hardware-wallets",
+  "optionalDependencies": {
+    "@ledgerhq/hw-transport-node-hid": "5.3.0"
+  },
   "publishConfig": {
     "access": "public"
   },

packages/hardware-wallets/src.ts/ledger-transport.ts

@@ -1,12 +1,29 @@
 "use strict";
 
-import hid from "@ledgerhq/hw-transport-node-hid";
-
 export type TransportCreator = {
     create: () => Promise<Transport>;
 };
 
-export const transports: { [ name: string ]: TransportCreator } = {
-    "hid": hid,
-    "default": hid
-};
+let hidCache: Promise<typeof import("@ledgerhq/hw-transport-node-hid")> = null;
+
+const hidWrapper = Object.freeze({
+    create: function(): Promise<Transport> {
+        // Load the library if not loaded
+        if (hidCache == null) {
+            hidCache = import("@ledgerhq/hw-transport-node-hid").then((hid) => {
+                if (hid.create == null) { return hid["default"]; }
+                return hid;
+            });
+        }
+
+        return hidCache.then((hid) => {
+            console.log(hid, hid.create);
+            return hid.create()
+        });
+    }
+});
+
+export const transports: { [ name: string ]: TransportCreator } = Object.freeze({
+    "hid": hidWrapper,
+    "default": hidWrapper
+});