> that still means I have to wait for the tsc to complete Without fork it. the webpack need to wait the checker to finish checking everything before it compile

> that still means I have to wait for the tsc to complete Without fork it. the webpack need to wait the checker to finish checking everything before it compiles even just one file. With a separate checker, it don't. The ts-loader will eject a perfectly normal js file without caring the typing is valid or not. And webpack can do the rest of works as quick as possible. It like different of do it in serial and do it in parallel. The latter will utilize the resources better although not absolutely more efficient.