Explicit promise for requestProvider, fix throws

Author: wbobeirne

src/client.ts

@@ -13,14 +13,16 @@ export interface GetProviderParameters {
 }
 
 export function requestProvider(_: GetProviderParameters = {}): Promise<WebLNProvider> {
-  if (typeof window === 'undefined') {
-    throw new Error('Must be called in a browser context');
-  }
+  return new Promise((resolve, reject) => {
+    if (typeof window === 'undefined') {
+      return reject(new Error('Must be called in a browser context'));
+    }
 
-  const webln: WebLNProvider = (window as any).webln;
-  if (!webln) {
-    throw new MissingProviderError('Your browser has no WebLN provider');
-  }
+    const webln: WebLNProvider = (window as any).webln;
+    if (!webln) {
+      return reject(new MissingProviderError('Your browser has no WebLN provider'));
+    }
 
-  return webln.enable().then(() => webln);
+    webln.enable().then(() => resolve(webln));
+  });
 }