Angular 2 实现 RouteReuseStrategy

Question

我实现了RouteReuseStrategy建议here并且还更新了一点，因为在 shouldAttach 上 routeConfig.path 是空的，处理程序没有被缓存。我有 @angular/router: 3.4.7。

import {RouteReuseStrategy, DetachedRouteHandle, ActivatedRouteSnapshot} from "@angular/router"

export class CustomReuseStrategy implements RouteReuseStrategy {

    handlers: {[key: string]: DetachedRouteHandle} = {};
    currentPath: string = '';

    shouldDetach(route: ActivatedRouteSnapshot): boolean {
        return true
    }

    store(route: ActivatedRouteSnapshot, handle: DetachedRouteHandle): void {
        this.handlers[route.routeConfig.path] = handle
    }

    shouldAttach(route: ActivatedRouteSnapshot): boolean {
        // todo route.routeConfig.path was empty
        if (!!this.currentPath && !!this.handlers[this.currentPath]) {
            route.routeConfig.path = this.currentPath;
            return true
        } else {
            return false
        }
    }

    retrieve(route: ActivatedRouteSnapshot): DetachedRouteHandle {
        if (!route.routeConfig) return null;
        return this.handlers[route.routeConfig.path]
    }

    shouldReuseRoute(future: ActivatedRouteSnapshot, curr: ActivatedRouteSnapshot): boolean {
        this.currentPath = curr.routeConfig && curr.routeConfig.path;

        return future.routeConfig === curr.routeConfig
    }

    deleteHandler(handler:string) {
        this.handlers[handler] && delete this.handlers[handler]
    }

}

一切正常，除了当我第三次尝试导航回路线时出现以下错误:

EXCEPTION: Uncaught (in promise): Error: Cannot reattach ActivatedRouteSnapshot with a different number of children
Error: Cannot reattach ActivatedRouteSnapshot with a different number of children
    at setFutureSnapshotsOfActivatedRoutes (http://localhost:4200/js/vendor.bundle.js:93110:15) [angular]
    at createNode (http://localhost:4200/js/vendor.bundle.js:93091:9) [angular]
    at http://localhost:4200/js/vendor.bundle.js:93131:16 [angular]
    at Array.map (native) [angular]
    at createOrReuseChildren (http://localhost:4200/js/vendor.bundle.js:93124:26) [angular]
    at createNode (http://localhost:4200/js/vendor.bundle.js:93086:41) [angular]
    at http://localhost:4200/js/vendor.bundle.js:93128:24 [angular]
    at Array.map (native) [angular]
    at createOrReuseChildren (http://localhost:4200/js/vendor.bundle.js:93124:26) [angular]
    at createNode (http://localhost:4200/js/vendor.bundle.js:93086:41) [angular]
    at createRouterState (http://localhost:4200/js/vendor.bundle.js:93072:33) [angular]
    at MapSubscriber.project (http://localhost:4200/js/vendor.bundle.js:26366:153) [angular]
    at MapSubscriber._next (http://localhost:4200/js/vendor.bundle.js:15890:35) [angular]
    at MapSubscriber.Subscriber.next (http://localhost:4200/js/vendor.bundle.js:4861:18) [angular]
    at MergeMapSubscriber.notifyNext (http://localhost:4200/js/vendor.bundle.js:19133:30) [angular]
    at InnerSubscriber._next (http://localhost:4200/js/vendor.bundle.js:106234:21) [angular]
    at InnerSubscriber.Subscriber.next (http://localhost:4200/js/vendor.bundle.js:4861:18) [angular]
    at MapSubscriber._next (http://localhost:4200/js/vendor.bundle.js:15896:26) [angular]
    at MapSubscriber.Subscriber.next (http://localhost:4200/js/vendor.bundle.js:4861:18) [angular]
    at ReduceSubscriber._complete (http://localhost:4200/js/vendor.bundle.js:36808:30) [angular]
    at ReduceSubscriber.Subscriber.complete (http://localhost:4200/js/vendor.bundle.js:4886:18) [angular]
    at MergeMapSubscriber._complete (http://localhost:4200/js/vendor.bundle.js:19125:30) [angular]
    at MergeMapSubscriber.Subscriber.complete (http://localhost:4200/js/vendor.bundle.js:4886:18) [angular]
    at ArrayObservable._subscribe (http://localhost:4200/js/vendor.bundle.js:12465:24) [angular]
    at ArrayObservable.Observable._trySubscribe (http://localhost:4200/js/vendor.bundle.js:221:25) [angular]
    at ArrayObservable.Observable.subscribe (http://localhost:4200/js/vendor.bundle.js:209:27) [angular]
    at MergeMapOperator.call (http://localhost:4200/js/vendor.bundle.js:19075:23) [angular]
    at Observable.subscribe (http://localhost:4200/js/vendor.bundle.js:206:22) [angular]
    at ReduceOperator.call (http://localhost:4200/js/vendor.bundle.js:36763:23) [angular]
    at Observable.subscribe (http://localhost:4200/js/vendor.bundle.js:206:22) [angular]
    at MapOperator.call (http://localhost:4200/js/vendor.bundle.js:15867:23) [angular]
    at Observable.subscribe (http://localhost:4200/js/vendor.bundle.js:206:22) [angular]
    at Object.subscribeToResult (http://localhost:4200/js/vendor.bundle.js:5096:27) [angular]
...

Answer 1

我有同样的问题，并且在过去一周一直在尝试。看起来它现在对我来说很好用。 主要挑战是为任何给定路由定义唯一键。当您使用子路由和延迟加载配置您的应用程序时，我发现 RouteReuseStrategy 变得有点复杂，无法理解和定义每个路由的键。我尝试解释我的理解，希望这些信息对您有所帮助。

RouteReuseStrategy
我试图找出 RouteReuseStrategy 方法调用和参数详细信息以生成唯一 key ，并通过调试我的应用程序得出下图。注意到有时阶段参数传递给方法调用并尝试在 RouteReuseStrategy 实现中忽略这些参数。

自定义重用策略

RouteReuseStrategy 实现:

/* tslint:disable */
import {ActivatedRouteSnapshot, DetachedRouteHandle, Params, RouteReuseStrategy} from "@angular/router";

interface RouteStorageObject {
    snapshot: ActivatedRouteSnapshot;
    handle: DetachedRouteHandle;
}

export class CustomReuseStrategy implements RouteReuseStrategy {
    storedRoutes: { [key: string]: RouteStorageObject } = {};

    getFurthestDecendantParams(route: ActivatedRouteSnapshot, sum: any): ActivatedRouteSnapshot {
        if (route.children.length > 0) {
            let child: ActivatedRouteSnapshot = route.children[0];
            sum.sum                           = sum.sum + this.sumParams(child.params);
            return this.getFurthestDecendantParams(child, sum);
        }
        return route;
    }

    sumParams(params: Params): string {
        return Object.keys(params).reduce((param, key) => {
            return param + params[key];
        }, "");
    }

    calcKey(route: ActivatedRouteSnapshot) {
        let paramKey = {
            sum: ""
        }
        if (route.children.length > 0) {
            this.getFurthestDecendantParams(route, paramKey).params;
        } else {
            paramKey.sum = this.sumParams(route.params);
        }
        if (paramKey.sum != "") {
            paramKey.sum = "_" + paramKey.sum;
        }
        return route.data.key + paramKey.sum;
    }

    public shouldDetach(route: ActivatedRouteSnapshot): boolean {
        console.info("CustomReuseStrategy.shouldDetach() - route key: " + this.calcKey(route));
        return !("product" === this.calcKey(route));
    }


    public store(route: ActivatedRouteSnapshot, handle: DetachedRouteHandle): void {
        let storedRoute: RouteStorageObject = {
            snapshot: route,
            handle: handle
        };
        console.info("CustomReuseStrategy.store() - route key: " + this.calcKey(route));
        this.storedRoutes[this.calcKey(route)] = storedRoute;
    }


    public shouldAttach(route: ActivatedRouteSnapshot): boolean {
        console.info("CustomReuseStrategy.shouldAttach() - route key: " + this.calcKey(route));
        return this.storedRoutes[this.calcKey(route)] !== undefined;
    }

    public retrieve(route: ActivatedRouteSnapshot): DetachedRouteHandle {
        console.info("CustomReuseStrategy.retrieve() - route key: " + this.calcKey(route));
        if (this.storedRoutes[this.calcKey(route)] === undefined) {
            /* Just return undefined */
            return null;
        } else {
            return this.storedRoutes[this.calcKey(route)].handle;
        }
    }


    public shouldReuseRoute(future: ActivatedRouteSnapshot, curr: ActivatedRouteSnapshot): boolean {
        let returnValue = (future.routeConfig === curr.routeConfig);
        if (future.routeConfig != null && curr.routeConfig != null) {
            returnValue = this.calcKey(future) === this.calcKey(curr);
            console.info("CustomReuseStrategy.shouldReuseRoute() - future: " + this.calcKey(future) + ", curr: " + this.calcKey(curr) +
                ", future.routeConfig.path:" + future.routeConfig.path + ", curr.routeConfig.path:" + curr.routeConfig.path + ", returnValue: " + returnValue);
        } else {
            console.info("CustomReuseStrategy.shouldReuseRoute() - future: " + this.calcKey(future) + ", curr: " + this.calcKey(curr) +
                ", future.routeConfig:" + future.routeConfig + ", curr.routeConfig:" + curr.routeConfig + ", returnValue: " + returnValue);
        }
        return returnValue;
    }
}

总结

在我的应用程序中定义了以下内容，RouteReuseStrategy 工作正常。

• 使用数据键和子延迟加载定义路由
• 只有一个路由导出
• 每条路线的唯一键
• Angular 版本 2.4.10 和 Router 版本 3.4.10

引用

• How to implement RouteReuseStrategy shouldDetach for specific routes in Angular 2