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A collection of useful components, directives and pipes for Angular.

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Jaspero/ng-helpers

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@jaspero/ng-helpers

A collection of useful components, directives and pipes for Angular applications.

Every item (component, directive and pipe) is published in a separate module, making it easy to just import modules your application will use and not increase bundle size unnecessarily.

Installation

To install this library, run:

$ npm install --save @jaspero/ng-helpers

Then import any Module you need. For example if you need the ClickOutsideDirective import the ClickOutsideModule.

Components

Directives

ClickOutsideDirective

This directive listens for emitted events on the window object and emits if the event doesn't contain the target element.

Example

<div (jpClickOutside)="doSomething()"></div>

Use Cases

  • Closing modals, dropdowns, mobile navigations when clicked outside.
  • Toggling off one item when another is clicked (accordion)

Outputs

name description
jpClickOutside Emits when current element isn't contained in the event

Inputs

name type default description
clickOutsideEventType string 'click' event to listen for
clickOutsideBlock boolean false if true jpClickOutside doesn't emit

FormTouchOnHoverDirective

This directive requires a FormGroup or FormArray then on mouseenter loops over all controls and marks them touched.

Example

<form [formGroup]="someForm">
  <input type="text" formControlName="someControl">

  <!--We wrapp the button so that we get mouseover event's even when the submit is disabled-->
  <div jpFormTouchOnHover>
    <button type="submit" [disabled]="someForm.invalid">Save</button>
  </div>
</form>

Use Cases

  • This directive is particularly useful when you want to provide information on why the submit button is disabled. Since hovering over it will trigger any validation on the form.

Outputs

name description
jpFormTouchOnHover Emits when controls finish looping and every element was touched

Inputs

name type default description
jpFormTouched FormGroup or FormArray null set of controls to loop over

StopPropagationDirective

Listens for the emitted event on the target element and simply forwards it along and calls event.stopPropagation().

Example

  <button (jpStopPropagation)="doSomething()">Click</button>

Use Cases

  • When ever you need to stopPropagation on an event, you can use this directive rather then passing the event along

Outputs

name description
jpStopPropagation Emits the original event after calling stopPropagation

Inputs

name type default description
preventDefault boolean false should event.preventDefault() also get called.
stopPropagationEventType string 'click' what event to listen for
condition boolean or (event) => boolean undefined a condition to check before calling event.stopPropagation()

DebounceChangeDirective

Listens for the emitted event on the target element and simply forwards it along after debounceTime.

Example

  <input type="text" (jpDebounceChange)="doSomething()" />

Use Cases

  • When ever you need to emit events with a delay

Outputs

name description
jpDebounceChange emits original event after debounceTime

Inputs

name type default description
debounceTime number 500 value to pass to the debounceTime pipe
debounceChangeEventType string 'keyup' what event to listen for
emitOnlyOnChange boolean false only emit event if the value changes

TrackByFieldDirective

Example

<div *ngFor="let item of items; jpTrackByField:'test'"></div>
@NgModule({
  imports: [TrackByFieldModule.defaultKey()]
})
export class Module {}

LoadClickDirective

Listens for the emitted click event on the target element and add loading class.

Example

  <button [jpLoadClick]="save()">Submit</button>

Use Cases

  • For preventing double click on the submit button.

Inputs

name type default description
jpLoadClick Observable null
loadClickClass string 'loading'
loadClickStopPropagation boolean false Should stopPropagation be called.
loadClickEventType string 'click'
loadClickPreventDefault boolean false Should preventDefault be called.
disableAttribute boolean true Should the disabled attribute be attached to the element.

Pipes

EnumPipe

A very simple pipe that returns an array of {key: number, value: string} objects from an enum.

Example

  <select>
    <option *ngFor="let item of someEnum | jpEnum" [value]="item.key">
      {{item.value}}
    </option>
  </select>

Use Cases

  • It's most commonly used to easily iterate over an enum in a select

Input Value

value type description
value enum Supports any enum value. Provide it in typescript someEnum = SomeEnum to iterate over in html.

Parameters

No parameters for EnumPipe

SanitizePipe

Simplifies using of DomSanitizer. The pipe accepts any value and then tries to sanitize it to the desired format.

Example

<div [innerHtml]="unsanitizedHtml | jpSanitize:'html'"></div>

Use Cases

  • Rendering raw html, styles...

Input Value

value type description
value string Accepts any unsanitized string and runs it through DomSanitizer

Parameters

param type default description
type html or style or script or url or resourceUrl html Type of entry value. This determines what DomSanitizer method get's used

TimePassedPipe

This pipe takes a date as input and returns the elapsed time since that date as a number in the desired format.

Example

<div>
 {{someDate | jpTimePassed:null:timePassedType.Minute}} minutes ago
</div>

Use Cases

  • Displaying elapsed time

Input Value

value type description
value Date any date

Parameters

param type default description
dateTwo Date current date This is the ending date in the interval. It defaults to the current date.
type TimePassedType TimePassedType.Minute In what time format should the elapsed time be returned in.

EnumKeyFormatPipe

Example

<div *ngFor="let item of someObject | jpArrayFromObject">
  <span>KEY: {{item.key}}</span>
  <span>VALUE: {{item.value}}</span>
</div>

Use Cases

  • This pipe is useful when ever you need to iterate an object in your template

Input Value

value type description
value object any object

Parameters

No parameters for ArrayFromObjectPipe

Decorators

OnChange

A decorator for change detection on properties

Example

export class AppComponent {
  @OnChange<string>((value, simpleChange) => {
      console.log(`Title is changed to: ${value}`);
  })
  @Input()
  title: string;
}

JpFunction

Decorator for methods used by LoadClickDirective.
Wraps them in function and expects return of type Observable.

Parameters

value type description
take number When JpFunction is called programmatically by default append take(1) to Observable. Pass 0 to skip take operator.

Example

@JpFunction()
waitFor(milliseconds: number = 1000) {
  return of(true).pipe(
    delay(milliseconds)
  );
}
@JpFunction({take: 2})
count() {
  return interval(10).pipe(
    tap((index) => {
      console.log(index);
    })
  );
}

ngOnInit() {
  // Triggers console.log for 0 and 1
  this.count();
}

License

MIT © Jaspero Ltd