Fixing use of undefined.
Fixing use of undefined.

mbrowne/typescript-dci,hippich/typescript,hippich/typescript,mbebenita/shumway.ts,popravich/typescript,hippich/typescript,mbebenita/shumway.ts,mbrowne/typescript-dci,fdecampredon/jsx-typescript-old-version,popravich/typescript,mbrowne/typescript-dci,mbrowne/typescript-dci,popravich/typescript,mbebenita/shumway.ts,fdecampredon/jsx-typescript-old-version,fdecampredon/jsx-typescript-old-version