Material Design

Linear Progress

Linear progress screenshot

The MDC Linear Progress component is a spec-aligned linear progress indicator component adhering to the Material Design progress & activity requirements.

Design & API Documentation

Installation

npm install @material/linear-progress

Basic Usage

HTML Structure

<div role="progressbar" class="mdc-linear-progress" aria-label="Example Progress Bar" aria-valuemin="0" aria-valuemax="1" aria-valuenow="0">
  <div class="mdc-linear-progress__buffering-dots"></div>
  <div class="mdc-linear-progress__buffer"></div>
  <div class="mdc-linear-progress__bar mdc-linear-progress__primary-bar">
    <span class="mdc-linear-progress__bar-inner"></span>
  </div>
  <div class="mdc-linear-progress__bar mdc-linear-progress__secondary-bar">
    <span class="mdc-linear-progress__bar-inner"></span>
  </div>
</div>

Accessibility

Progress bars conform to the WAI-ARIA Progressbar Specification. The supported ARIA attributes for this progress bar are:

Attribute Description
aria-label Label indicating how the progress bar should be announced to the user.
aria-valuemin The minimum numeric value of the progress bar, which should always be 0.
aria-valuemax The maximum numeric value of the progress bar, which should always be 1.
aria-valuenow A numeric value between aria-valuemin and aria-valuemax indicating the progress value of the primary progress bar. This attribute is removed in indeterminate progress bars.

Note that aria-label, aria-valuemin, and aria-valuemax are static and must be configured in the HTML. aria-valuenow is updated dynamically by the foundation when the progress value is updated in determinate progress bars.

Styles

@use "@material/linear-progress/mdc-linear-progress";

JavaScript Instantiation

import { MDCLinearProgress } from '@material/linear-progress';

const linearProgress = new MDCLinearProgress(document.querySelector('.mdc-linear-progress'));

See Importing the JS component for more information on how to import JavaScript.

CSS Modifiers

The provided modifiers are:

Class Description
mdc-linear-progress--indeterminate Puts the linear progress indicator in an indeterminate state.
mdc-linear-progress--reversed Reverses the direction of the linear progress indicator.
mdc-linear-progress--closed Hides the linear progress indicator.

Sass Mixins

Mixin Description
bar-color($color) Sets the color of the progress bar
buffer-color($color) Sets the color of the buffer bar and dots

Using the Foundation Class

MDC Linear Progress ships with an MDCLinearProgressFoundation class that external frameworks and libraries can use to integrate the component. As with all foundation classes, an adapter object must be provided. The adapter for linear progress must provide the following functions, with correct signatures:

Method Signature Description
addClass(className: string) => void Adds a class to the root element.
removeAttribute(attributeName: string) => void Removes the specified attribute from the root element.
removeClass(className: string) => void Removes a class from the root element.
hasClass(className: string) => boolean Returns boolean indicating whether the root element has a given class.
forceLayout() => void Force-trigger a layout on the root element. This is needed to restart animations correctly.
getPrimaryBar() => Element Returns the primary bar element.
getBuffer() => Element Returns the buffer element.
setAttribute(attributeName: string, value: string) => void Sets the specified attribute on the root element.
setStyle(el: Element, styleProperty: string, value: string) => void Sets the inline style on the given element.

MDCLinearProgressFoundation API

MDC Linear Progress Foundation exposes the following methods:

Method Signature Description
setDeterminate(value: boolean) => void Toggles the component between the determinate and indeterminate state.
setProgress(value: number) => void Sets the progress bar to this value. Value should be between [0, 1].
setBuffer(value: number) => void Sets the buffer bar to this value. Value should be between [0, 1].
setReverse(value: boolean) => void Reverses the direction of the linear progress indicator.
open() => void Puts the component in the open state.
close() => void Puts the component in the closed state.

MDCLinearProgress API

MDC Linear Progress exposes the following methods:

Method Signature Description
set determinate(value: boolean) => void Toggles the component between the determinate and indeterminate state.
set progress(value: number) => void Sets the progress bar to this value. Value should be between [0, 1].
set buffer(value: number) => void Sets the buffer bar to this value. Value should be between [0, 1].
set reverse(value: boolean) => void Reverses the direction of the linear progress indicator.
open() => void Puts the component in the open state.
close() => void Puts the component in the closed state.