ionic-framework/packages/angular-server/src/ionic-server-module.ts

import { DOCUMENT } from '@angular/common';
import { APP_ID, NgModule } from '@angular/core';
import { BEFORE_APP_SERIALIZED } from '@angular/platform-server';
import { hydrateDocument } from '@ionic/core/hydrate';

// @dynamic
@NgModule({
  providers: [
    {
      provide: BEFORE_APP_SERIALIZED,
      useFactory: hydrateIonicComponents,
      multi: true,
      deps: [DOCUMENT, APP_ID]
    }
  ]
})
export class IonicServerModule {}

// @dynamic
export function hydrateIonicComponents(doc: any, appId: any) {
  return () => {
    return hydrateDocument(doc, {
      clientHydrateAnnotations: false
    })
    .then(hydrateResults => {
      hydrateResults.diagnostics.forEach(d => {
        if (d.type === 'error') {
          console.error(d.messageText);
        } else if (d.type === 'debug') {
          console.debug(d.messageText);
        } else {
          console.log(d.messageText);
        }
      });

      if (doc.head != null) {
        const styleElms = doc.head.querySelectorAll('style[data-styles]') as NodeListOf<HTMLStyleElement>;
        for (let i = 0; i < styleElms.length; i++) {
          styleElms[i].setAttribute('ng-transition', appId);
        }
      }

      if (doc.body != null) {
        const ionPages = doc.body.querySelectorAll('.ion-page.ion-page-invisible') as NodeListOf<HTMLElement>;
        for (let i = 0; i < ionPages.length; i++) {
          ionPages[i].classList.remove('ion-page-invisible');
        }
      }
    });
  };
}