feat(@angular/cli): load reflect only on dev

[filipesilva]

reflect-metadata is not needed in AOT builds. It's the biggest polyfill and the cause for a significant startup time increase.

Note: this will make ng build --prod --no-aot builds for new projects not work. The workaround is to move reflect-metadata back into the common polyfills. We should discuss if this is ok.

Fix #6325

[filipesilva]

Blocking for now, discussion is needed regarding the --prod --no-aot break. Maybe a warning is enough.

[ishitatsuyuki]

I think this should be done by on-the-fly replacement just like the one in bootstrapModuleFactory.

[filipesilva]

@ishitatsuyuki some setups might still need it, especially if they are using decorators other than Angular.

[ishitatsuyuki]

We can make the feature opt-in, and I don't think environment is where we should configure it. Environment is purely runtime credentials, not for build options.

[intellix]

Does this still work? Tried this locally and with these changes my app doesn't run anymore :)
I'm building via: ng build --target=production -e ${NG_ENV:-prod} --aot
And running in OSX Chrome 59

Uncaught TypeError: jo.getOwnMetadata is not a function

[rokerkony]

fyi:
I tried it locally and get same result as @intellix

I run it as:
npm run ng build -- -prod --aot=true --base-href=/static/frontend-som/

"@angular/*": 4.2.2
"@angular/cli": 1.1.1

[devoto13]

I agree with @ishitatsuyuki that it's better be implemented as opt-in build-time replacement than putting polyfills in the environment files.

We want to get rid of this polyfill only when doing AoT, not when building for specific environment. And environment is orthogonal to AoT. In my project I have 5 environments, so it's not very convenient to paste polyfills in every environment file just to get this optimization. Also warning will be tricky to implement when running AoT build for the custom environment or without --prod meta flag.

While the obvious benefit of current implementation is simplicity I think it is wrong to abuse environment for this feature. Another point is that current implementation can be done by end user without need to eject or mess up with CLI itself.

I would rather have a flag, like --strip-reflect-polyfill, which will add noop-loader/null-loader for these two specific polyfill imports (so they won't be included in the bundle). For backwards compatibility it will be opt-in feature, but in 2.0 it will be enabled by default when AoT is enabled (breaking change) and there will be opt-out flag for people, who need this polyfills even in AoT. Like --no-strip-reflect-polyfill. Does it make sense?

[awerlang]

Is this somehow merged already? Because on a production build reflect-metadata is not on the bundle.

"@angular/cli": "1.3.0-rc.3"

ng build --prod --aot --bo -sm --vendor-chunk=false --output-hashing=none

Notice: I removed "polyfills: "polyfills.ts"" from .angular-cli.json, in order to produce a single output file (besides inline.bundle.js).

I can't tell if this was working before, because we rely on rollup for production and thought we'd try angular-cli. Replacing reflect-metadata with core-js it "works", only the app seems to not take data from @ngrx/store, but this might be unrelated. EDIT: removing the --bo async data is working again.

[filipesilva]

This isn't something we're going to do for now. It's pretty risky for projects that need Reflect. An alternative solution will be added in the future.

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