Too many node process exhaust the memory

Hi,
I deploy theia base app on linux, after running 2 days I find that the memory of the system is exhasted and have to restart it.
When the app starts, there are 30 node process. If I open a new client in browser, the process grows 15. If I refresh the browser, the process grows 5. Repeat these operations, the memory will be exhausted at last. In my opinion, once the client disconnected the correspoding process will be closed automaticly.So what’s the problem of this situation?
Bellow is the process number after refreshing the browser

jump@d-qcsh3-thiaoouba-cloud-ide-dev-01:/big-angel$ ps -aux | grep -i 'node' | wc -l
196
jump@d-qcsh3-thiaoouba-cloud-ide-dev-01:/big-angel$ ps -aux | grep -i 'node' | wc -l
206
jump@d-qcsh3-thiaoouba-cloud-ide-dev-01:/big-angel$ ps -aux | grep -i 'node' | wc -l
206
jump@d-qcsh3-thiaoouba-cloud-ide-dev-01:/big-angel$ ps -aux | grep -i 'node' | wc -l
211
jump@d-qcsh3-thiaoouba-cloud-ide-dev-01:/big-angel$ ps -aux | grep -i 'node' | wc -l
216
jump@d-qcsh3-thiaoouba-cloud-ide-dev-01:/big-angel$ ps -aux | grep -i 'node' | wc -l
216
jump@d-qcsh3-thiaoouba-cloud-ide-dev-01:/big-angel$ ps -aux | grep -i 'node' | wc -l
216
jump@d-qcsh3-thiaoouba-cloud-ide-dev-01:/big-angel$ ps -aux | grep -i 'node' | wc -l
221
jump@d-qcsh3-thiaoouba-cloud-ide-dev-01:/big-angel$ ps -aux | grep -i 'node' | wc -l
221
jump@d-qcsh3-thiaoouba-cloud-ide-dev-01:/big-angel$ ps -aux | grep -i 'node' | wc -l
226
jump@d-qcsh3-thiaoouba-cloud-ide-dev-01:/big-angel$ ps -aux | grep -i 'node' | wc -l
226
jump@d-qcsh3-thiaoouba-cloud-ide-dev-01:/big-angel$ ps -aux | grep -i 'node' | wc -l
226
jump@d-qcsh3-thiaoouba-cloud-ide-dev-01:/big-angel$ ps -aux | grep -i 'node' | wc -l
231

@tsmaeder