Default to production builds

[StephenFluin]

🚀 Feature request

I know this is tough due to it being a breaking change with the ecosystem, but I think ng build should do a production build by default.

Command (mark with an x)

- [x] build

Description

Most of the time, developers should be building for production, and serving for development. It would save a lot of time overall if ng build defaulted to production mode.

Describe the solution you'd like

During the update process to 9 (or some other version), prompt the user if they want to keep the current behavior or migrate to the new behavior, and then default all new projects with ng new to production by default.

Describe alternatives you've considered

None

[filipesilva]

We actually followed this exact reasoning in 1.6, and some users were caught by surprise in a nasty way (#10191), prompting us to revert it (angular/devkit@b9704dc).

I can't imagine doing this change now would go any better since users have been used to npm run build not doing prod builds for much longer now.

@alexeagle WDYT?

[mgechev]

Based on our discussion today, the feature makes a lot of sense. We should be very explicit in the way we communicate that we're using --prod.

[StephenFluin]

@mgechev Are you saying the right behavior is to default to non-prod or to production mode?

[clydin]

Build —> production by default
Serve —> development by default

When the changeover happens (9.0? Sooner?) the concept would be that in addition to messaging in the release notes, a informational message would be displayed on build execution to provide ample opportunity to inform the user of the change in behavior.

[filipesilva]

Using our current setup, we could make the default options for build in angular.json contain the production settings, and have a separate dev configuration for development settings. Then ng serve would target the dev configuration for its build options.

We'd also have to provide good messages in the CLI about this. Users are used to using the --prod flag.

[StephenFluin]

Awesome! Perhaps we could consider an update schematic that adds a "legacyBuildDefault"= true somewhere to existing applications that update to help folks with the transition.