How to do incremental build when it recompiled

[martinko2009]

Environment

My OS is win7.I use webpack-dev-server 1.14.1.

I know webpack-dev-server will watch the source files which are changed.After these files are changed, webpack-dev-server will recompile by doing incremental build.

But I find it still recompile by doing full build. I want to know how to do incremental build when recompile.

I use command line style to start webpack-dev-server.Here is the command like below

webpack-dev-server --inline --hot --progress --port 9090

I still use the webpack.config.js