impact of global import file in angular 2

Question

I have a file name service.imports.ts having following code.

export { Http, Response, Headers, RequestOptions } from '@angular/http'
export { Observable } from 'rxjs/Observable'
export { Injectable } from '@angular/core';
export * from 'rxjs/add/operator/map';
export * from 'rxjs/add/operator/catch';

and call that file in my angular 2 service.ts file by

import { Http } from '../service.imports'

As you can see i am only calling Http module and ignoring Response, Headers, RequestOptions.

how angular 2 handles this situation? will it load all the modules mentioned in service.imports.ts or it only loads the modules which are being called where that service.imports.ts is used i.e only Http?

I have the performance concern.

score 1 · Accepted Answer · edited May 23 '17 at 12:17

1

No, these imports don't matter. The compilation step will get rid of them.

It would be different if you'd add them to

@NgModule({
  imports: [...],
  declarations: [...],
  bootstrap: [...],
  entryComponents: [...]
})

Using barrels was even an Angular style guide suggestion a while ago, until they discovered it regularly causes issues like Angular 2 DI Error - EXCEPTION: Can't resolve all parameters

edited May 23 '17 at 12:17

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answered Apr 05 '17 at 07:46

Günter Zöchbauer

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so do you suggest me to design my app in this way? Is it a good practice? – Salman Lone Apr 05 '17 at 07:52
The Angular team moved away from it because it causes problems. I wouldn't create a file that collects all imports. I'd do it to some degree, like for modules (same granularity as `NgModule`), but not for a whole application. – Günter Zöchbauer Apr 05 '17 at 07:54
Thank you for the suggestion. – Salman Lone Apr 05 '17 at 07:59

impact of global import file in angular 2

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