ionic-framework/angular/src/directives/navigation/stack-utils.ts

import { ComponentRef } from '@angular/core';
import { ActivatedRoute, NavigationExtras, Router } from '@angular/router';
import { AnimationBuilder, NavDirection, RouterDirection } from '@ionic/core';

export const insertView = (views: RouteView[], view: RouteView, direction: RouterDirection): RouteView[] => {
  if (direction === 'root') {
    return setRoot(views, view);
  } else if (direction === 'forward') {
    return setForward(views, view);
  } else {
    return setBack(views, view);
  }
};

const setRoot = (views: RouteView[], view: RouteView) => {
  views = views.filter((v) => v.stackId !== view.stackId);
  views.push(view);
  return views;
};

const setForward = (views: RouteView[], view: RouteView) => {
  const index = views.indexOf(view);
  if (index >= 0) {
    views = views.filter((v) => v.stackId !== view.stackId || v.id <= view.id);
  } else {
    views.push(view);
  }
  return views;
};

const setBack = (views: RouteView[], view: RouteView) => {
  const index = views.indexOf(view);
  if (index >= 0) {
    return views.filter((v) => v.stackId !== view.stackId || v.id <= view.id);
  } else {
    return setRoot(views, view);
  }
};

export const getUrl = (router: Router, activatedRoute: ActivatedRoute): string => {
  const urlTree = router.createUrlTree(['.'], { relativeTo: activatedRoute });
  return router.serializeUrl(urlTree);
};

export const isTabSwitch = (enteringView: RouteView, leavingView: RouteView | undefined): boolean => {
  if (!leavingView) {
    return true;
  }
  return enteringView.stackId !== leavingView.stackId;
};

export const computeStackId = (prefixUrl: string[] | undefined, url: string): string | undefined => {
  if (!prefixUrl) {
    return undefined;
  }
  const segments = toSegments(url);
  for (let i = 0; i < segments.length; i++) {
    if (i >= prefixUrl.length) {
      return segments[i];
    }
    if (segments[i] !== prefixUrl[i]) {
      return undefined;
    }
  }
  return undefined;
};

export const toSegments = (path: string): string[] => {
  return path
    .split('/')
    .map((s) => s.trim())
    .filter((s) => s !== '');
};

export const destroyView = (view: RouteView | undefined): void => {
  if (view) {
    view.ref.destroy();
    view.unlistenEvents();
  }
};

export interface StackEvent {
  enteringView: RouteView;
  direction: RouterDirection;
  animation: NavDirection | undefined;
  tabSwitch: boolean;
}

export interface RouteView {
  id: number;
  url: string;
  stackId: string | undefined;
  element: HTMLElement;
  ref: ComponentRef<any>;
  savedData?: any;
  savedExtras?: NavigationExtras;
  unlistenEvents: () => void;
  animationBuilder?: AnimationBuilder;
}