na aula 8, quando executo o comando npm start dá o erro abaixo, com um log de erros enorme

insira seu código aqui'tsc' não é reconhecido como um comando interno
ou externo, um programa operável ou um arquivo em lotes.
npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! client@1.0.0 tsc:w: `tsc -w`
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the client@1.0.0 tsc:w script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.

npm ERR! A complete log of this run can be found in:
npm ERR!     C:\Users\vitor\AppData\Roaming\npm-cache\_logs\2018-03-16T11_49_17_949Z-debug.log
npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! client@1.0.0 start: `npm run tsc:w`
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the client@1.0.0 start script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.

npm ERR! A complete log of this run can be found in:
npm ERR!     C:\Users\vitor\AppData\Roaming\npm-cache\_logs\2018-03-16T11_49_18_122Z-debug.log