[ts-migrate][.] Init tsconfig.json file

Co-authored-by: ts-migrate <>

test/fixtures/mocha.ts

@@ -1,16 +1,23 @@
 "use strict";
 
+// @ts-expect-error TS(2580): Cannot find name 'require'. Do you need to install... Remove this comment to see the full error message
 const { host } = require("@jsdevtools/host-environment");
 
 if (host.browser) {
+  // @ts-expect-error TS(2304): Cannot find name 'mocha'.
   mocha.setup("bdd");
+  // @ts-expect-error TS(2304): Cannot find name 'mocha'.
   mocha.fullTrace();
+  // @ts-expect-error TS(2304): Cannot find name 'mocha'.
   mocha.asyncOnly();
+  // @ts-expect-error TS(2304): Cannot find name 'mocha'.
   mocha.checkLeaks();
+  // @ts-expect-error TS(2304): Cannot find name 'mocha'.
   mocha.globals(["$0", "$1", "$2", "$3", "$4", "$5", "ga", "gaplugins", "gaGlobal", "gaData"]);
 }
 
-beforeEach(function () {
+// @ts-expect-error TS(2304): Cannot find name 'beforeEach'.
+beforeEach(function(this: any) {
   // Most of our tests perform multiple AJAX requests,
   // so we need to increase the timeouts to allow for that
   this.currentTest.timeout(20000);