ng2-webstorage

###Local and session storage - angular4 service

This library provides an easy to use service to manage the web storages (local and session) from your ng2 application. It provides also two decorators to synchronize the component attributes and the web storages.

---

Index:

• Getting Started
• Services:
  • LocalStorageService
  • SessionStorageService
• Decorators:
  • @LocalStorage
  • @SessionStorage
• Known issues
• Modify and build

---

Getting Started

1. Download the library using npm npm install --save ng2-webstorage

2. Register the library in your module

   import {NgModule} from '@angular/core';
   import {BrowserModule} from '@angular/platform-browser';
   import {Ng2Webstorage} from 'ng2-webstorage';
   
   @NgModule({
   	declarations: [...],
   	imports: [
   		BrowserModule,
   		Ng2Webstorage,
   		//Ng2Webstorage.forRoot({ prefix: 'custom', separator: '.' }) The forRoot method allows to configure the prefix and the separator used by the library
   	],
   	bootstrap: [...]
   })
   export class AppModule {
   }

   If you're using systemJS, you have to reference the umd version of the lib in your config.

   	System.config({
   		map: { 
   			...,
   			'ng2-webstorage': 'node_modules/ng2-webstorage'
   		},
   		packages: {
   			...,
   			'ng2-webstorage': {main: 'bundles/core.umd.js', defaultExtension: 'js'}
   		}
   	});

3. Inject the services you want in your components and/or use the available decorators

   import {Component} from '@angular/core';
   import {LocalStorageService, SessionStorageService} from 'ng2-webstorage';
   
   @Component({
   	selector: 'foo',
   	template: `foobar`
   })
   export class FooComponent {
   
   	constructor(private localSt:LocalStorageService) {}
   
   	ngOnInit() {
   		this.localSt.observe('key')
   			.subscribe((value) => console.log('new value', value));
   	}
   
   }

   import {Component} from '@angular/core';
   import {LocalStorage, SessionStorage} from 'ng2-webstorage';
   
   @Component({
   	selector: 'foo',
   	template: `{{boundValue}}`,
   })
   export class FooComponent {
   
   	@LocalStorage()
   	public boundValue;
   
   }

Services

---

###LocalStorageService

Store( key:string, value:any ):void

create or update an item in the local storage

Params:

• key: String. localStorage key.
• value: Serializable. value to store.

Usage:

import {Component} from '@angular/core';
import {LocalStorageService} from 'ng2-webstorage';

@Component({
	selector: 'foo',
	template: `
		<section><input type="text" [(ngModel)]="attribute"/></section>
		<section><button (click)="saveValue()">Save</button></section>
	`,
})
export class FooComponent {

    attribute;

    constructor(private storage:LocalStorageService) {}

    saveValue() {
      this.storage.store('boundValue', this.attribute);
    }

}

---

Retrieve( key:string ):any

retrieve a value from the local storage

Params:

• key: String. localStorage key.

Result:

• Any; value

Usage:

import {Component} from '@angular/core';
import {LocalStorageService} from 'ng2-webstorage';

@Component({
	selector: 'foo',
	template: `
		<section>{{attribute}}</section>
		<section><button (click)="retrieveValue()">Retrieve</button></section>
	`,
})
export class FooComponent {

    attribute;

    constructor(private storage:LocalStorageService) {}

    retrieveValue() {
      this.attribute = this.storage.retrieve('boundValue');
    }

}

---

Clear( key?:string ):void

Params:

• key: (Optional) String. localStorage key.

Usage:

import {Component} from '@angular/core';
import {LocalStorageService, LocalStorage} from 'ng2-webstorage';

@Component({
	selector: 'foo',
	template: `
		<section>{{boundAttribute}}</section>
		<section><button (click)="clearItem()">Clear</button></section>
	`,
})
export class FooComponent {

    @LocalStorage('boundValue')
    boundAttribute;

    constructor(private storage:LocalStorageService) {}

    clearItem() {
      this.storage.clear('boundValue');
      //this.storage.clear(); //clear all the managed storage items
    }

}

---

Observe( key?:string ):EventEmitter

Params:

• key: String. localStorage key.

Result:

• Observable; instance of EventEmitter

Usage:

import {Component} from '@angular/core';
import {LocalStorageService, LocalStorage} from 'ng2-webstorage';

@Component({
	selector: 'foo',
	template: `{{boundAttribute}}`,
})
export class FooComponent {

    @LocalStorage('boundValue')
    boundAttribute;

    constructor(private storage:LocalStorageService) {}

    ngOnInit() {
      this.storage.observe('boundValue')
        .subscribe((newValue) => {
          console.log(newValue);
        })
    }

}

###SessionStorageService

The api is identical as the LocalStorageService's

Decorators

---

###@LocalStorage

Synchronize the decorated attribute with a given value in the localStorage

Params:

• storage key: (Optional) String. localStorage key, by default the decorator will take the attribute name.

Usage:

import {Component} from '@angular/core';
import {LocalStorage, SessionStorage} from 'ng2-webstorage';

@Component({
	selector: 'foo',
	template: `{{boundAttribute}}`,
})
export class FooComponent {

	@LocalStorage()
	public boundAttribute;

}

---

###@SessionStorage

Synchronize the decorated attribute with a given value in the sessionStorage

Params:

• storage key: (Optional) String. SessionStorage key, by default the decorator will take the attribute name.

Usage:

import {Component} from '@angular/core';
import {LocalStorage, SessionStorage} from 'ng2-webstorage';

@Component({
	selector: 'foo',
	template: `{{randomName}}`,
})
export class FooComponent {

	@SessionStorage('AnotherBoundAttribute')
	public randomName;

}

Known issues

---

• Serialization doesn't work for objects:

Ng2Webstorage's decorators are based upon accessors so the update trigger only on assignation. Consequence, if you change the value of a bound object's property the new model will not be store properly. The same thing will happen with a push into a bound array. To handle this cases you have to trigger manually the accessor.

import {LocalStorage} from 'ng2-webstorage';

class FooBar {

    @LocalStorage('prop')
    myArray;

    updateValue() {
        this.myArray.push('foobar');
        this.myArray = this.myArray; //does the trick
    }

}

Modify and build

---

npm install

Start the unit tests: npm run test

Start the unit tests: npm run test:watch

Start the dev server: npm run dev then go to http://localhost:8080/webpack-dev-server/index.html