Skip to content
Permalink
Branch: master
Find file Copy path
166 lines (150 sloc) 4.4 KB
/**
* @license
* Copyright Google Inc. 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 {DOCUMENT} from '@angular/common';
import {APP_ID, Injectable, NgModule} from '@angular/core';
export function escapeHtml(text: string): string {
const escapedText: {[k: string]: string} = {
'&': '&a;',
'"': '&q;',
'\'': '&s;',
'<': '&l;',
'>': '&g;',
};
return text.replace(/[&"'<>]/g, s => escapedText[s]);
}
export function unescapeHtml(text: string): string {
const unescapedText: {[k: string]: string} = {
'&a;': '&',
'&q;': '"',
'&s;': '\'',
'&l;': '<',
'&g;': '>',
};
return text.replace(/&[^;]+;/g, s => unescapedText[s]);
}
/**
* A type-safe key to use with `TransferState`.
*
* Example:
*
* ```
* const COUNTER_KEY = makeStateKey<number>('counter');
* let value = 10;
*
* transferState.set(COUNTER_KEY, value);
* ```
*
* @publicApi
*/
export type StateKey<T> = string & {__not_a_string: never};
/**
* Create a `StateKey<T>` that can be used to store value of type T with `TransferState`.
*
* Example:
*
* ```
* const COUNTER_KEY = makeStateKey<number>('counter');
* let value = 10;
*
* transferState.set(COUNTER_KEY, value);
* ```
*
* @publicApi
*/
export function makeStateKey<T = void>(key: string): StateKey<T> {
return key as StateKey<T>;
}
/**
* A key value store that is transferred from the application on the server side to the application
* on the client side.
*
* `TransferState` will be available as an injectable token. To use it import
* `ServerTransferStateModule` on the server and `BrowserTransferStateModule` on the client.
*
* The values in the store are serialized/deserialized using JSON.stringify/JSON.parse. So only
* boolean, number, string, null and non-class objects will be serialized and deserialzied in a
* non-lossy manner.
*
* @publicApi
*/
@Injectable()
export class TransferState {
private store: {[k: string]: {} | undefined} = {};
private onSerializeCallbacks: {[k: string]: () => {} | undefined} = {};
/** @internal */
static init(initState: {}) {
const transferState = new TransferState();
transferState.store = initState;
return transferState;
}
/**
* Get the value corresponding to a key. Return `defaultValue` if key is not found.
*/
get<T>(key: StateKey<T>, defaultValue: T): T {
return this.store[key] !== undefined ? this.store[key] as T : defaultValue;
}
/**
* Set the value corresponding to a key.
*/
set<T>(key: StateKey<T>, value: T): void { this.store[key] = value; }
/**
* Remove a key from the store.
*/
remove<T>(key: StateKey<T>): void { delete this.store[key]; }
/**
* Test whether a key exists in the store.
*/
hasKey<T>(key: StateKey<T>) { return this.store.hasOwnProperty(key); }
/**
* Register a callback to provide the value for a key when `toJson` is called.
*/
onSerialize<T>(key: StateKey<T>, callback: () => T): void {
this.onSerializeCallbacks[key] = callback;
}
/**
* Serialize the current state of the store to JSON.
*/
toJson(): string {
// Call the onSerialize callbacks and put those values into the store.
for (const key in this.onSerializeCallbacks) {
if (this.onSerializeCallbacks.hasOwnProperty(key)) {
try {
this.store[key] = this.onSerializeCallbacks[key]();
} catch (e) {
console.warn('Exception in onSerialize callback: ', e);
}
}
}
return JSON.stringify(this.store);
}
}
export function initTransferState(doc: Document, appId: string) {
// Locate the script tag with the JSON data transferred from the server.
// The id of the script tag is set to the Angular appId + 'state'.
const script = doc.getElementById(appId + '-state');
let initialState = {};
if (script && script.textContent) {
try {
initialState = JSON.parse(unescapeHtml(script.textContent));
} catch (e) {
console.warn('Exception while restoring TransferState for app ' + appId, e);
}
}
return TransferState.init(initialState);
}
/**
* NgModule to install on the client side while using the `TransferState` to transfer state from
* server to client.
*
* @publicApi
*/
@NgModule({
providers: [{provide: TransferState, useFactory: initTransferState, deps: [DOCUMENT, APP_ID]}],
})
export class BrowserTransferStateModule {
}
You can’t perform that action at this time.