Angular2 @LocalStorage

This little Angular2/typescript decorator makes it super easy to save and restore automatically a variable state in your directive (class property) using HTML5' LocalStorage.

Use

1. Download the library using npm or github: npm install --save angular2-localstorage

2. Register the LocalStorage in your boot.ts:

   import {LocalStorageService, LocalStorageSubscriber} from 'angular2-localstorage/LocalStorageEmitter';
   var appPromise = bootstrap(MyRootAppComponent, [ LocalStorageService ]);
      
   // register LocalStorage, this registers our change-detection.
   LocalStorageSubscriber(appPromise);

   or in your root component:

   import {Component} from "angular2/core";
   import {LocalStorageService} from "angular2-localstorage/LocalStorageEmitter";
   
   @Component({
       provider: [LocalStorageService]
   })
   export class AppRoot{
       constructor(storageService: LocalStorageService){}
   ...
   }

3. Use the LocalStorage decorator

import {LocalStorage, SessionStorage} from "angular2-localstorage/WebStorage";

class MySuperComponent {
    @LocalStorage() public lastSearchQuery:Object = {};
    @LocalStorage('differentLocalStorageKey') public lastSearchQuery:Object = {};
}

Note: Define always a default value at the property you are using @LocalStorage.

Note: The localstorage key is per default the property name. Define the first argument of @LocalStorage to set different one.

Note: Please don't store circular structures as this library uses JSON.stringify to encode before using LocalStorage.

Examples

@Component({
    selector: 'app-login',
    template: `
<form>
    <div>
        <input type="text" [(ngModel)]="username" placeholder="Username" />
        <input type="password" [(ngModel)]="password" placeholder="Password" />
    </div>
    
    <input type="checkbox" [(ngModel)]="rememberMe" /> Keep me logged in

    <button type="submit">Login</button>
</form>
    `
})
class AppLoginComponent {
    //here happens the magic. `username` is always restored from the localstorage when you reload the site
    @LocalStorage() public username:string = '';
    
    public password:string;
    
    //here happens the magic. `rememberMe` is always restored from the localstorage when you reload the site
    @LocalStorage() public rememberMe:boolean = false;
}

@Component({
    selector: 'admin-menu',
    template: `
<div *ngFor="#menuItem of menuItems() | mapToIterable; #i = index">
    <h2 (click)="hiddenMenuItems[i] = !!!hiddenMenuItems[i]">
        {{i}}: {{category.label}}
    </h2>
    <div style="padding-left: 15px;" [hidden]="hiddenMenuItems[i]">
        <a href>Some sub menu item 1</a>
        <a href>Some sub menu item 2</a>
        <a href>Some sub menu item 3</a>
    </div>
</div>
    `
})
class AdminMenuComponent {
    public menuItems = [{title: 'Menu1'}, {title: 'Menu2'}, {title: 'Menu3'}];

    //here happens the magic. `hiddenMenuItems` is always restored from the localstorage when you reload the site
    @LocalStorage() public hiddenMenuItems:Array<boolean> = [];
    
    //here happens the magic. `profile` is always restored from the sessionStorage when you reload the site from the current tab/browser. This is perfect for more sensitive information that shouldn't stay once the user closes the browser.
    @SessionStorage() public profile:any = {};
}