angular-cn/packages/router/src/create_router_state.ts

80 lines
3.3 KiB
TypeScript

/**
* @license
* Copyright Google LLC All Rights Reserved.
*
* Use of this source code is governed by an MIT-style license that can be
* found in the LICENSE file at https://angular.io/license
*/
import {BehaviorSubject} from 'rxjs';
import {DetachedRouteHandleInternal, RouteReuseStrategy} from './route_reuse_strategy';
import {ActivatedRoute, ActivatedRouteSnapshot, RouterState, RouterStateSnapshot} from './router_state';
import {TreeNode} from './utils/tree';
export function createRouterState(
routeReuseStrategy: RouteReuseStrategy, curr: RouterStateSnapshot,
prevState: RouterState): RouterState {
const root = createNode(routeReuseStrategy, curr._root, prevState ? prevState._root : undefined);
return new RouterState(root, curr);
}
function createNode(
routeReuseStrategy: RouteReuseStrategy, curr: TreeNode<ActivatedRouteSnapshot>,
prevState?: TreeNode<ActivatedRoute>): TreeNode<ActivatedRoute> {
// reuse an activated route that is currently displayed on the screen
if (prevState && routeReuseStrategy.shouldReuseRoute(curr.value, prevState.value.snapshot)) {
const value = prevState.value;
value._futureSnapshot = curr.value;
const children = createOrReuseChildren(routeReuseStrategy, curr, prevState);
return new TreeNode<ActivatedRoute>(value, children);
} else {
if (routeReuseStrategy.shouldAttach(curr.value)) {
// retrieve an activated route that is used to be displayed, but is not currently displayed
const detachedRouteHandle = routeReuseStrategy.retrieve(curr.value);
if (detachedRouteHandle !== null) {
const tree = (detachedRouteHandle as DetachedRouteHandleInternal).route;
setFutureSnapshotsOfActivatedRoutes(curr, tree);
return tree;
}
}
const value = createActivatedRoute(curr.value);
const children = curr.children.map(c => createNode(routeReuseStrategy, c));
return new TreeNode<ActivatedRoute>(value, children);
}
}
function setFutureSnapshotsOfActivatedRoutes(
curr: TreeNode<ActivatedRouteSnapshot>, result: TreeNode<ActivatedRoute>): void {
if (curr.value.routeConfig !== result.value.routeConfig) {
throw new Error('Cannot reattach ActivatedRouteSnapshot created from a different route');
}
if (curr.children.length !== result.children.length) {
throw new Error('Cannot reattach ActivatedRouteSnapshot with a different number of children');
}
result.value._futureSnapshot = curr.value;
for (let i = 0; i < curr.children.length; ++i) {
setFutureSnapshotsOfActivatedRoutes(curr.children[i], result.children[i]);
}
}
function createOrReuseChildren(
routeReuseStrategy: RouteReuseStrategy, curr: TreeNode<ActivatedRouteSnapshot>,
prevState: TreeNode<ActivatedRoute>) {
return curr.children.map(child => {
for (const p of prevState.children) {
if (routeReuseStrategy.shouldReuseRoute(child.value, p.value.snapshot)) {
return createNode(routeReuseStrategy, child, p);
}
}
return createNode(routeReuseStrategy, child);
});
}
function createActivatedRoute(c: ActivatedRouteSnapshot) {
return new ActivatedRoute(
new BehaviorSubject(c.url), new BehaviorSubject(c.params), new BehaviorSubject(c.queryParams),
new BehaviorSubject(c.fragment), new BehaviorSubject(c.data), c.outlet, c.component, c);
}