@material/linear-progress

Linear Progress

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

Design & API Documentation

• Guidelines
• Demo

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__buffer">
    <div class="mdc-linear-progress__buffer-bar"></div>
    <div class="mdc-linear-progress__buffer-dots"></div>
  </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.

RTL Localization

The direction of the progress bar follows the dir attribute on its nearest ancestor. For example, setting dir="rtl" on the progress root reverses the direction of the indicator. Where multiple dir attributes are specified in the tree, the one on the progress bar root takes precedence.

Styles

@use "@material/linear-progress";

@include linear-progress.core-styles;

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--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.
setAttribute(attributeName: string, value: string) => void	Sets the specified attribute on the root element.
setBufferBarStyle(styleProperty: string, value: string) => void	Sets the inline style on the buffer bar.
setPrimaryBarStyle(styleProperty: string, value: string) => void	Sets the inline style on the primary bar.
attachResizeObserver(callback: ResizeObserverCallback) => ResizeObserver | null	Returns a ResizeObserver that has had observe called on the root with the given callback (for animation performance gains on modern browsers). null if ResizeObserver is not implemented or polyfilled.
setStyle(styleProperty: string, value: string) => void	Sets the inline style on the root element.
getWidth() => number	Returns the width of the root.

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.
isDeterminate() => boolean	Whether or not the component is in determinate state.
setProgress(value: number) => void	Sets the progress bar to this value. Value should be between [0, 1].
getProgress() => number	The current progress value in the interval [0,1].
setBuffer(value: number) => void	Sets the buffer bar to this value. Value should be between [0, 1].
getBuffer() => number	The current buffer value in the interval [0,1].
open() => void	Puts the component in the open state.
close() => void	Puts the component in the closed state.
isClosed() => boolean	Whether or not the progress indicator is closed.

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].
open() => void	Puts the component in the open state.
close() => void	Puts the component in the closed state.