Add var returns

packages/dev-utils/src/callback_error_reporter.ts

@@ -7,7 +7,7 @@ const expect = chai.expect;
 
 export const callbackErrorReporter = {
     reportNoErrorCallbackErrors(done: DoneCallback, expectToBeCalledOnce = true) {
-        return <T>(f?: (value: T) => void) => {
+        const callback = <T>(f?: (value: T) => void) => {
             const wrapped = (value: T) => {
                 if (_.isUndefined(f)) {
                     done();
@@ -24,9 +24,10 @@ export const callbackErrorReporter = {
             };
             return wrapped;
         };
+        return callback;
     },
     reportNodeCallbackErrors(done: DoneCallback, expectToBeCalledOnce = true) {
-        return <T>(f?: (value: T) => void) => {
+        const callback = <T>(f?: (value: T) => void) => {
             const wrapped = (error: Error | null, value: T | undefined) => {
                 if (!_.isNull(error)) {
                     done(error);
@@ -47,6 +48,7 @@ export const callbackErrorReporter = {
             };
             return wrapped;
         };
+        return callback;
     },
     assertNodeCallbackError(done: DoneCallback, errMsg: string) {
         const wrapped = <T>(error: Error | null, value: T | undefined) => {