Barista - Progress bar

The <dt-progress-bar> creates a simple progress bar. It is possible to set the value for the progress bars as well as setting a min and max value. The color property can be set to specify the color of the progress. The color depends on the theme the progress bars is in. The value will be clamped between the min and max values.

<dt-progress-bar
  [value]="75"
  aria-label="Progress between 0 and a hundred for something"
></dt-progress-bar>

Imports

You have to import the DtProgressBarModule when you want to use the dt-progress-bar.

@NgModule({
  imports: [DtProgressBarModule],
})
class MyModule {}

Inputs

Name	Type	Default	Description
`value`	`number`	`0`	Gets and sets the value on the progress-bar.
`min`	`number`	`0`	Gets and sets the minimum value on the progress bar
`max`	`number`	`100`	Gets and sets the maximum value on the progress bar
`align`	`'start' \| 'end'`	`start`	Sets the alignment of the progress element to the star or to the end.

Using the align input the alignment of the progress bar can be changed to end.

<dt-progress-bar
  [value]="30"
  [align]="'end'"
  aria-label="Progerss between 0 and a 100 for something."
></dt-progress-bar>

Outputs

Name	Type	Description
`valueChange`	`EventEmitter<{ oldValue: number, newValue: number }>`	Event emitted when the progress bar value changes.

<p>Value passed to the progress bar: {{ value }}</p>
<dt-progress-bar
  (valueChange)="changed($event)"
  [value]="value"
  aria-label="Progress between min and max visualized"
></dt-progress-bar>
<div>
  <button dt-button (click)="value = value - 10">decrease by 10</button>
  <button dt-button (click)="value = value + 10">increase by 10</button>
</div>
<p *ngIf="oldValue !== null">
  Event: OldValue: {{ oldValue }}
  <br />
  NewValue: {{ newValue }}
</p>

Properties

Name	Type	Description
`percentage`	`number`	Gets the percentage used to render the progress

Progress bar description

The <dt-progress-bar-description> component lets you add a description to the progress-bar. It utilises ng-content selection within the <dt-progress-bar> component to position the description correctly. Use the description to provide more insight into what the progress bar actually indicates.

<dt-progress-bar ...>
  <dt-progress-bar-description>
    Rich text describing the progress...
  </dt-progress-bar-description>
  <dt-progress-bar></dt-progress-bar>
</dt-progress-bar>

<dt-progress-bar [value]="75" aria-label="Progress for loading a large dataset">
  <dt-progress-bar-description>
    We found more than 100 results. This may take a while, consider narrowing
    your search.
  </dt-progress-bar-description>
</dt-progress-bar>

Progress bar count

The <dt-progress-bar-count> component lets you add a count to the progressbar which usually is a textual representation of the progress displayed (i.e. 80/100 days). It utilises ng-content selection within the <dt-progress-bar> component to position the count data correctly. Any values passed to the progress-bar-count are not affected by the progress-bar component min/max values. Use the count to display a text representation of the progress.

<dt-progress-bar ...>
  <dt-progress-bar-count>80/100 days</dt-progress-bar-count>
  <dt-progress-bar></dt-progress-bar>
</dt-progress-bar>

<dt-progress-bar
  (valueChange)="changed($event)"
  [value]="value"
  aria-label="Progress value for something"
>
  <dt-progress-bar-count>
    <strong>{{ value }}/{{ max }} days</strong>
  </dt-progress-bar-count>
</dt-progress-bar>
<div>
  <button dt-button (click)="value = value - 10">decrease by 10</button>
  <button dt-button (click)="value = value + 10">increase by 10</button>
</div>
<p *ngIf="oldValue !== null">
  Event: OldValue: {{ oldValue }}
  <br />
  NewValue: {{ newValue }}
</p>

<dt-progress-bar
  (valueChange)="changed($event)"
  [value]="value"
  aria-label="Progress of loading a large set of data"
>
  <dt-progress-bar-description>
    We found more than 100 results. This may take a while, consider narrowing
    your search.
  </dt-progress-bar-description>
  <dt-progress-bar-count>
    <strong>{{ value }}/{{ max }} days</strong>
  </dt-progress-bar-count>
</dt-progress-bar>
<div>
  <button dt-button (click)="value = value - 10">decrease by 10</button>
  <button dt-button (click)="value = value + 10">increase by 10</button>
</div>
<p *ngIf="oldValue !== null">
  Event: OldValue: {{ oldValue }}
  <br />
  NewValue: {{ newValue }}
</p>

Colors

The progress bar can be colored based on its color theme palette.

<dt-progress-bar
  [value]="45"
  [color]="color"
  aria-label="Progress of something with changing color hints"
>
</dt-progress-bar>
<div>
  <dt-button-group [value]="color" (valueChange)="changed($event)">
    <dt-button-group-item value="main">main</dt-button-group-item>
    <dt-button-group-item value="accent">accent</dt-button-group-item>
    <dt-button-group-item value="warning">warning</dt-button-group-item>
    <dt-button-group-item value="error">error</dt-button-group-item>
    <dt-button-group-item value="recovered">recovered</dt-button-group-item>
  </dt-button-group>
</div>

Dark background

Progress bars can be placed on dark background.

<div class="dt-example-dark" dtTheme=":dark">
  <dt-progress-bar [value]="value" aria-label="Data fetching progress">
    <dt-progress-bar-description>
      We found more than 100 results. This may take a while, consider narrowing
      your search.
    </dt-progress-bar-description>
    <dt-progress-bar-count>{{ value }}% loaded</dt-progress-bar-count>
  </dt-progress-bar>
</div>

Accessibility

Progress bars should be given a meaningful label via aria-label or aria-labelledby.

Progress bar in use

While the loading distractor does not indicate how long something will take, the progress bar displays how far along the process is.

The progress bar should be used to display a distinct progress of a process or status, i.e. a download progress or used status of a disk.

Animation

Once the bar has finished loading, it will fade out after 1s and the loaded content will move up to fill the space where the progress bar used to be. The fade out transition takes 500ms.

Progress bar animation

Progress bar with indicator

When the progress value reaches a defined threshold an indicator can be used to highlight the number as shown in the following example.

<dt-progress-bar
  (valueChange)="changed($event)"
  [value]="value"
  aria-label="Progress for loading a large amount of data"
>
  <dt-progress-bar-description>
    We found more than 100 results. This may take a while, consider narrowing
    your search.
  </dt-progress-bar-description>
  <dt-progress-bar-count>
    <strong>
      <span [dtIndicator]="metricHasProblem(value)" dtIndicatorColor="error">
        {{ value }}
      </span>
      /{{ max }} days
    </strong>
  </dt-progress-bar-count>
</dt-progress-bar>
<div>
  <button dt-button (click)="value = value - 10">decrease by 10</button>
  <button dt-button (click)="value = value + 10">increase by 10</button>
</div>
<p *ngIf="oldValue !== null">
  Event: OldValue: {{ oldValue }}
  <br />
  NewValue: {{ newValue }}
</p>