Today I have observe one of error , which while we are extracting and building with node.
I was facing some challenges,
FATAL ERROR: heap limit Allocation failed - JavaScript heap out of memory.
node --max_old_space_size=8000
By using this in command line or environment variable setting we can able to extend size of allocation.
Generally Visual studio or Other tool through while running application we will face such problem.
For watch on command and extend the allocation size :
node --max_old_space_size=8000 ./node_modules/@angular/cli/bin/ng build --watch
this will be same command you can use in powershall windows or cmd.
It will resolve allocation size memory issue.