What is the use of Angular 2 hashtags in template ?

Angular2 hashtag is a syntax used to declare DOM element as variable and these templates render as an HTML file.

• #: variable declaration
• (): event binding
• []: property binding
• [()]: two-way property binding
• {{}}: interpolation

Template reference variables are a little gem that allows getting a lot of nice things done with Angular. It relies on a simple hashtag to create a reference to an element in a template.
Syntax: 

<input #searchBox keyword="search(searchBox.value)">

In above syntax, it creates reference to the input element that can be used later in the templates.
Example: 

import {Component} from 'angular2/core';

@Component({
   selector: 'pv-app',
   templateUrl: 'components/harry/hello.component.html'
})

export class pvApp {}import {Component} from 'angular2/core';

@Component({
   selector: 'pv-app',
   templateUrl: 'components/pv/hello.component.html'
})

export class pvApp {}

<input type="text" #pv>
 {{ pv.value }}

In above example, pv refers to HTML element object instance for input. So, pv has all the properties and methods of HTML Elements. (id, name, etc.)