2 * ============LICENSE_START==========================================
4 * ===================================================================
5 * Copyright (C) 2019 AT&T Intellectual Property. All rights reserved.
6 * ===================================================================
8 * Unless otherwise specified, all software contained herein is licensed
9 * under the Apache License, Version 2.0 (the "License");
10 * you may not use this software except in compliance with the License.
11 * You may obtain a copy of the License at
13 * http://www.apache.org/licenses/LICENSE-2.0
15 * Unless required by applicable law or agreed to in writing, software
16 * distributed under the License is distributed on an "AS IS" BASIS,
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18 * See the License for the specific language governing permissions and
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21 * Unless otherwise specified, all documentation contained herein is licensed
22 * under the Creative Commons License, Attribution 4.0 Intl. (the "License");
23 * you may not use this documentation except in compliance with the License.
24 * You may obtain a copy of the License at
26 * https://creativecommons.org/licenses/by/4.0/
28 * Unless required by applicable law or agreed to in writing, documentation
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34 * ============LICENSE_END============================================
39 import { Inject, Injectable, PLATFORM_ID } from '@angular/core';
40 import { makeStateKey, TransferState } from '@angular/platform-browser';
41 import { isPlatformBrowser, isPlatformServer } from '@angular/common';
42 import { of } from 'rxjs';
43 import { tap } from 'rxjs/operators';
45 let isBrowser: boolean;
46 let isServer: boolean;
47 let transferState: TransferState;
52 export class TransferStateService {
54 private state: TransferState,
55 @Inject(PLATFORM_ID) private platformId: any
57 transferState = state;
58 isBrowser = isPlatformBrowser(this.platformId);
59 isServer = isPlatformServer(this.platformId);
63 export const preserveServerState = (
65 emptyResult: any = null
67 const key = makeStateKey(keyName);
68 return (target: any, propertyKey: string, descriptor: PropertyDescriptor) => {
69 const method = descriptor.value;
70 descriptor.value = function() {
71 if (isBrowser && transferState.hasKey(key)) {
72 const state = transferState.get(key, emptyResult);
76 return method.apply(this, arguments).pipe(
79 transferState.set(key, res);