bootstrap collapsible directive in angular2

I decided to to take another looking easy challenge - to make collapsible directive with angular2 by myself.
I will use css of great bootstrap framework.
Bootstrap framework has collapsed CSS class for make elements disappear (by applying "display:none" style), and "in" class, which when it set on collapsed element - makes it to show up.
So, once we already know (after doing couple of things in previous posts) how to create some angular2 components -

Lets create parent component (App)

//our root app component
import {Component} from 'angular2/core'
import {Collapse} from 'src/collapse'
@Component({
  selector: 'my-app',
  providers: [],
  template: `
    <div>
      <h2 (click)="isCollapsed = !isCollapsed">click here</h2>
       
      <div class="collapse in" [collapse]="isCollapsed" >
        <div class="well">
          panel panel panel
        </div>
      </div>
      
    </div>
  `,
  directives: [Collapse]
})
export class App {
  isCollapsed:boolean = false;
  constructor() {}
} 

Directive is not dead

Yes there are directives in angular2 too. Their goal is to be decorator-style directives, which do not have templates. According to angular2 documentation "directive changes the appearance or behavior of a DOM element."
Note that for changing class property of directive's root element i go to use HostBinding factory

import {Directive, Input, HostBinding} from 'angular2/core'
@Directive({selector: '[collapse]'})
export class Collapse { 
 

  @HostBinding('class.in') 
  private isCollapsed:boolean;
  
  
  @Input()
  private set collapse(value:boolean) { 
     
      if(!value){   
        this.isCollapsed = true; 
      }else { 
        this.isCollapsed = false; 
      }
     
  }
  constructor() {}  
}

Animation

Everybody knows that collapse is not looking cool without animation.
Everyone who little familiar with css, knows that for make animation you may use CSS3 Transitions.
For example:

.collapsing{
 height:80px; 
 overflow:hidden;
 transition:height 0.4s ease-in-out;
}

After applying this class on some element, its height will smoothly change to 80 pixels.

Trick

Animation will not work for elements those height is not specified (auto). So, for make some html elements to collapse with animation we must give them their own initial css height. One of the ways to measure the actual height of the element - is to use scrollHeight property.

    this.h = elem.scrollHeight;   

Lets use the trick on our the directive

import {Directive, Input, HostBinding, ElementRef} from 'angular2/core'
@Directive({selector: '[collapse]'})
export class Collapse { 

  @HostBinding('class.collapsing') 
  private isCollapsing:boolean   

    // style
  @HostBinding('style.height') 
  private height:string;
  
  
  @Input()
  private set collapse(value:boolean) { 
    if(value!==undefined){
      if(value){ 
        this.hide(); 
      }else { 
        this.show();
      }
    }
    //
  }
  constructor(public el: ElementRef) {
    
    this.measureHeight(); 
  }  
  measureHeight() {
    let elem = this.el.nativeElement;
    //lets be sure the element has display:block style
    elem.className = elem.className.replace('collapse', '');
    this.h = elem.scrollHeight;
   
  }
  hide(){
    this.height = this.h +'px'
    setTimeout(() => {
        this.height = '0px';
        this.isCollapsing = true;//apply 'collapsing' class
    },1); 
  }
  show() {
    this.height = '0px'
    setTimeout(() => {
        this.height = this.h + 'px';
        this.isCollapsing = true;//apply 'collapsing' class
    },1);
  }  
}

Here is running code: Hope you have fun reading...

creating chart component - angular2

After creating my first component which displays current time, i want to try something little bit complicate.
This time lets create a component which displays chart:

For draw a chart i will use jquery flot library which is one of libraries/plugins which let you to create beautiful charts.
According to jquery flot docs - for draw a chart you need to pass html element(selector), data and options to plot plugin, like this:

$.plot( selector, dataset, options);

Component

As in previous case, lets create component

import {Component, ElementRef} from 'angular2/core';

@Component({
  selector: 'flot',
  template: `<div>loading</div>`

})

export class FlotCmp {
  private dataset;
  private options;
  private width = '100%';
  private height = 220;

  
  constructor(public el: ElementRef) {
        this.dataset = [{label: "line1",data:  [[1, 130], [2, 40], [3, 80], [4, 160], [5, 159], [6, 370], [7, 330], [8, 350], [9, 370], [10, 400], [11, 330], [12, 350]]}];
        this.options = {
            series: {
                lines: { show: true },
                points: {
                    radius: 3,
                    show: true
                }
            }
        };
        
        let plotArea = $(this.el.nativeElement).find('div');
        plotArea.css({
            width: this.width,
            height: this.height
        });
        $.plot( plotArea, this.dataset, this.options);

  }//end of constructor
}

Yes!!! Now the chart s created!!!
Note that for access the html element on which i want to apply the chart, i'v used ElementRef module

Passing properties

Our next goal is to make newly created component configurable - e.g. ability to pass dataset, options, width, height configuration properties through the attributes:

  
     <flot [options]="splineOptions" [dataset]="dataset" height="550px" width="100%"></flot>
 

"Piece of cake!" you may say, like in previous case use the "input" factory and you done:

import {Component, ElementRef, Input} from 'angular2/core';

@Component({
  selector: 'flot',
  template: `<div>loading</div>`

})
//this will cause error!!!
export class FlotCmp{

  private width = '100%';
  private height = 220;
  static chosenInitialized = false;
  
  @Input() private  options: any;
  @Input() private  dataset:any;
  @Input() private  width:string;
  @Input() private  height:string;
      
   
  constructor(public el: ElementRef) {
        plotArea.css({
            width: this.width, 
            height: this.height
        });
        $.plot( plotArea, this.dataset, this.options);        
  }
  ...  

Bad idea! No chart created anymore.
But why? Because the constructor runs before input setters passing their values. We must move plot initiating logic to some later phase. I find the solution here. This guy uses AfterViewInit factory:

import {Component, ElementRef, Input, AfterViewInit} from 'angular2/core';

@Component({
  selector: 'flot',
  template: `<div>loading</div>`

})

export class FlotCmp  implements AfterViewInit{

  private width = '100%';
  private height = 220;
  static chosenInitialized = false;
  
  @Input() private  options: any;
  @Input() private  dataset:any;
  @Input() private  width:string;
  @Input() private  height:string;
 
  constructor(public el: ElementRef) {}

  ngAfterViewInit() {
      if(!FlotCmp.chosenInitialized) {
        let plotArea = $(this.el.nativeElement).find('div').empty();
        plotArea.css({
            width: this.width, 
            height: this.height
        });
        $.plot( plotArea, this.dataset, this.options);    
        FlotCmp.chosenInitialized = true;
      }
  } 
} 

Now the chart initiating logic is in the ngAfterViewInit method which activates after properies already set.
Hope you have fun reading!
More posts about angular2 stuff (used for me as inspiration source)

Building my first directive with angular2

Recently i started to play with recently released beta of angular2.
I'm totally beginner and i want to build very simple thing.
I want to build the component (component is like directive in angular 1.) that displays current time in format given as a parameter (through the attribute format).

  
  
    <now format="'h:mm:ss'"></now>
  

When rendered HTML, should look like this:

How to run angular2?

First thing you need then you want to run angular2 is environment.
You can use one of angular2 starter kits like this one Or just open plunker and select "Editor" -> "New" -> "AngularJs" -> "2.0.x TS" and viola!! you are angular2 programmer!

Component

The first basic thing in angular2 is component, so: Lets create a component:

import {Component} from 'angular2/core'

@Component({
  selector: 'now',
  template: `
{{date}}
`      
})
export class Now {
  private date;
  constructor() { 
    this.date =  new Date(); 
  } 
} 

Yoo hoo!!! The component created and running!!!
And it displays the current date!!!
But one little disturbing thing is that date appears raw , which is little bit ugly...

So lets improve the component by formatting the output.

Pipe (Filter)

Like in sngular 1. there are filters in angular2, they called pipes

import {Component} from 'angular2/core'

@Component({
  selector: 'now',
  template: `
{{date | date :'dd/MM/yyyy'}}
`      
})

Getting value from attribute (The tricky part)

As we already said the desired format should be passed through the attribute. But how to access this attribute from inside component constructor? Fortunately there is Attribute module which enables you to inject attribute into constructor parameters:

import {Component, Attribute} from 'angular2/core'
export class Now {
   private date;
   
  constructor(@Attribute("format") format) { 
    this.format = format;
    this.date =  new Date(); 

  } 

} 

Better way

After Lenin's older brother was executed because he tried(but failed) to kill king of Russia with bomb, young Lenin said "We will go different way"...
After looking at angular2 docs i found better (more angular2mish) way which says that if we want to pass attribute to component we must use square brackets :

  
  
    <now [format]="'h:mm:ss'"></now>
  

I will use @Input module instead of @attribute

import {Component,  Input} from 'angular2/core'

@Component({
  selector: 'now',
  template: `
      
{{date | date: _format}}
    `
})
export class Now {
   private date;
   @Input() set format(formatName:string){
     this._format = formatName;
   
   }   
  constructor() { 
    this.date =  new Date(); 
  } 

} 

How to update time each second?

Little nice thing to add here is ability to update the time displayed in directive each second. For achieve this i'm using ES6 fat arrow syntax

export class Now {
   private date;
   @Input() set format(formatName:string){
     this._format = formatName;
   
   }   
  constructor() { 
    this.date =  new Date(); 
    
    setInterval(() => {
        this.date =  new Date();
     }, 1000);
  } 

} 

View it on plunker: