ng build -prod vs ng build --prod --build-optimizer=true

Question

My Angular project is @Angular4.3.3

ng build -prod

Takes 77 seconds to make a build

ng build --prod --bu

Answer 1

--build-optimizer and --vendor-chunk

From Angular CLI Docs:

When using Build Optimizer the vendor chunk will be disabled by default. You can override this with --vendor-chunk=true.

Total bundle sizes with Build Optimizer are smaller if there is no separate vendor chunk because having vendor code in the same chunk as app code makes it possible for Uglify to remove more unused code.