make: Entering directory '/var/www/html/node_modules/uws/build'
  CXX(target) Release/obj.target/uws/src/Extensions.o
  CXX(target) Release/obj.target/uws/src/Group.o
In file included from ../src/Group.cpp:2:0:
../src/Hub.h:7:10: fatal error: zlib.h: No such file or directory
 #include <zlib.h>
          ^~~~~~~~
compilation terminated.
uws.target.mk:98: recipe for target 'Release/obj.target/uws/src/Group.o' failed
make: *** [Release/obj.target/uws/src/Group.o] Error 1
make: Leaving directory '/var/www/html/node_modules/uws/build'
gyp ERR! build error 
gyp ERR! stack Error: `make` failed with exit code: 2
gyp ERR! stack     at ChildProcess.onExit (/usr/share/node-gyp/lib/build.js:258:23)
gyp ERR! stack     at emitTwo (events.js:126:13)
gyp ERR! stack     at ChildProcess.emit (events.js:214:7)
gyp ERR! stack     at Process.ChildProcess._handle.onexit (internal/child_process.js:198:12)
gyp ERR! System Linux 4.15.0-66-generic
gyp ERR! command "/usr/bin/node" "/usr/bin/node-gyp" "rebuild"
gyp ERR! cwd /var/www/html/node_modules/uws
gyp ERR! node -v v8.10.0
gyp ERR! node-gyp -v v3.6.2
gyp ERR! not ok