jest-environment-jsdom: add ? to options parameter

Kent C. Dodds · web-flow · commit 38ca9267de93 · 2018-01-05T16:00:08.000-07:00
As suggested by @thymikee in jestjs#5227 (comment)
diff --git a/packages/jest-environment-jsdom/src/index.js b/packages/jest-environment-jsdom/src/index.js
@@ -23,7 +23,7 @@ class JSDOMEnvironment {
   errorEventListener: ?Function;
   moduleMocker: ?ModuleMocker;
 
-  constructor(config: ProjectConfig, options: EnvironmentOptions = {}) {
+  constructor(config: ProjectConfig, options?: EnvironmentOptions = {}) {
     this.dom = new JSDOM(
       '<!DOCTYPE html>',
       Object.assign(
