@ngx-universal/state-transfer NPM

@ngx-universal/state-transfer

State transferring utility for Angular Universal

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NOTICE

This 4.x.x branch is intented to work with @angular v4.x.x. If you're developing on a later release of Angular than v4.x.x, then you should probably choose the appropriate version of this library by visiting the master branch.

Prerequisites

This library depends on Angular v4.0.0. Older versions contain outdated dependencies, might produce errors.

Also, please ensure that you are using Typescript v2.3.4 or higher.

Getting started

Installation

You can install @ngx-universal/state-transfer using npm

npm install @ngx-universal/state-transfer --save

Examples

ng-seed/universal is an officially maintained seed project, showcasing common patterns and best practices for @ngx-universal/state-transfer.

Related packages

The following packages may be used in conjunction with @ngx-universal/state-transfer:

Adding `@ngx-universal/state-transfer` to your project (SystemJS)

Add map for @ngx-universal/state-transfer in your systemjs.config

'@ngx-universal/state-transfer': 'node_modules/@ngx-universal/state-transfer/bundles/state-transfer.umd.min.js'

app.server.module configuration

Import ServerStateTransferModule using the mapping '@ngx-universal/state-transfer' and append ServerStateTransferModule.forRoot({...}) within the imports property of app.server.module (considering the app.server.module is the server module in Angular Universal application).

...
import { ServerStateTransferModule, StateTransferService } from '@ngx-universal/state-transfer';
...

@NgModule({
  imports: [
    BrowserModule.withServerTransition({
      appId: 'my-app-id'
    }),
    ServerModule,
    ServerStateTransferModule.forRoot(),
    AppModule
  ],
  ...
  bootstrap: [AppComponent]
})
export class AppServerModule {
  constructor(private readonly stateTransfer: StateTransferService) {
  }

  ngOnBootstrap = () => {
    this.stateTransfer.set('test_key', JSON.stringify({'value': 'test'}));
    this.stateTransfer.inject();
  }
}

app.browser.module configuration

Import BrowserStateTransferModule using the mapping '@ngx-universal/state-transfer' and append BrowserStateTransferModule.forRoot({...}) within the imports property of app.browser.module (considering the app.browser.module is the browser module in Angular Universal application).

...
import { BrowserStateTransferModule } from '@ngx-universal/state-transfer';
...

@NgModule({
  imports: [
    BrowserModule.withServerTransition({
      appId: 'my-app-id'
    }),
    BrowserStateTransferModule.forRoot(),
    AppModule
  ],
  ...
  bootstrap: [LayoutMainComponent]
})
export class AppBrowserModule {
}

app.module configuration

Import HttpTransferModule using the mapping '@ngx-universal/state-transfer' and append HttpTransferModule.forRoot({...}) within the imports property of app.module (considering the app.module is the core module in Angular application).

...
import { HttpTransferModule } from '@ngx-universal/state-transfer';
...

@NgModule({
  imports: [
    BrowserModule,
    HttpTransferModule.forRoot(),
    ...
  ],
  ...
  bootstrap: [AppComponent]
})
export class AppModule {
  ...
}

:+1: So good! @ngx-universal/state-transfer will now transfer the state from the server platform to the browser platform.

Usage

StateTransferService has the following methods:

initialize(state: Map<string, any>): initializes the STATE using an existing Map<string, any>
get(key: string): gets some object from STATE, by key
set(key: string, value: any): puts some object to STATE
inject(): injects the STATE inside a <script> block (between the <head>...</head> tags)

The following example shows how to read the STATE value transferred from the server platform to the browser platform, using the configuration above.

app.browser.module

...
import { BrowserStateTransferModule, DEFAULT_STATE_ID } from '@ngx-universal/state-transfer';
...

@NgModule({
  imports: [
    BrowserModule.withServerTransition({
      appId: 'my-app-id'
    }),
    BrowserStateTransferModule.forRoot(),
    AppModule
  ],
  ...
  bootstrap: [LayoutMainComponent]
})
export class AppBrowserModule {
  constructor() {
    // get `STATE` value (injected by the server platform)
    let stateValue = undefined;
    
    const win: any = window;
    
    if (win && win[DEFAULT_STATE_ID])
      stateValue = win[DEFAULT_STATE_ID];
    
    // do something with the value acquired
    // whatever you want ...
  }
}