fix(discovery-client): Monkeypatch uncatchable throw from mdns-js (#2433

)

discovery-client/__mocks__/mdns-js.js

@@ -20,4 +20,6 @@ const __mockReset = () => {
   createBrowser.mockReturnValue(__mockBrowser)
 }
 
-module.exports = {tcp, createBrowser, __mockBrowser, __mockReset}
+const ServiceType = function () {}
+
+module.exports = {tcp, createBrowser, ServiceType, __mockBrowser, __mockReset}

discovery-client/src/index.js

@@ -4,11 +4,11 @@
 
 import EventEmitter from 'events'
 import escape from 'escape-string-regexp'
-import mdns from 'mdns-js'
 import toRegex from 'to-regex'
 import differenceBy from 'lodash/differenceBy'
 import xorBy from 'lodash/xorBy'
 
+import MdnsBrowser from './mdns-browser'
 import {poll, stop, type PollRequest} from './poller'
 import {
   createServiceList,
@@ -178,8 +178,7 @@ export class DiscoveryClient extends EventEmitter {
   _startBrowser (): void {
     this._stopBrowser()
 
-    const browser = mdns
-      .createBrowser(mdns.tcp('http'))
+    const browser = MdnsBrowser()
       .once('ready', () => browser.discover())
       .on('update', service => this._handleUp(service))
       .on('error', error => this.emit('error', error))

discovery-client/src/mdns-browser.js

@@ -0,0 +1,23 @@
+// @flow
+// mdns browser wrapper
+import mdns, {ServiceType} from 'mdns-js'
+import type {Browser} from 'mdns-js'
+
+monkeyPatchThrowers()
+
+export default function MdnsBrowser (): Browser {
+  return mdns.createBrowser(mdns.tcp('http'))
+}
+
+function monkeyPatchThrowers () {
+  // this method can throw (without emitting), so we need to patch this up
+  const originalServiceTypeFromString = ServiceType.prototype.fromString
+
+  ServiceType.prototype.fromString = function (...args) {
+    try {
+      originalServiceTypeFromString.apply(this, args)
+    } catch (error) {
+      console.warn(error)
+    }
+  }
+}

flow-typed/npm/mdns-js_v1.0.x.js

@@ -17,18 +17,19 @@ declare module 'mdns-js' {
   }
 
   declare module.exports: {
-    createBrowser: (serviceType: ServiceType) => Browser,
-    tcp: (type: string) => ServiceType
+    createBrowser: (serviceType: MdnsServiceType) => Browser,
+    tcp: (type: string) => MdnsServiceType,
+    ServiceType: any
   }
 
   declare type Browser = mdns$Browser
 
-  declare type ServiceType = mdns$ServiceType
+  declare type MdnsServiceType = mdns$ServiceType
 
   declare type BrowserService = {
     addresses: Array<string>,
     query: Array<string>,
-    type?: Array<ServiceType>,
+    type?: Array<MdnsServiceType>,
     txt?: Array<string>,
     port?: number,
     fullname?: string,