@rsmdc/tab-indicator

Tab Indicator

A Tab Indicator is a visual guide that shows which Tab is active.

Design & API Documentation

• Material Design guidelines: Anatomy of Tabs
• Demo

Installation

npm install @rsmdc/tab-indicator

Basic Usage

HTML Structure

<span class="mdc-tab-indicator">
  <span class="mdc-tab-indicator__content"></span>
</span>

Styles

@import "@rsmdc/tab-indicator/mdc-tab-indicator";

JavaScript Instantiation

import {MDCTabIndicator} from '@rsmdc/tab-indicator';

const tabIndicator = new MDCTabIndicator(document.querySelector('.mdc-tab-indicator'));

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

Variants

Active Indicator

Add the mdc-tab-indicator--active class to the mdc-tab-indicator element to make the Tab Indicator active.

Indicator Types and Transitions

The Tab Indicator may be represented in one of two ways:

• Underline, indicated by the mdc-tab-indicator__content--underline class
• Icon, indicated by the mdc-tab-indicator__content--icon class

NOTE: One of these classes must be applied to the Tab Indicator's content element.

The Tab Indicator may transition in one of two ways:

• Slide, the default behavior
• Fade, indicated by the mdc-tab-indicator--fade class

Sliding Underline Indicator

<span class="mdc-tab-indicator">
  <span class="mdc-tab-indicator__content mdc-tab-indicator__content--underline"></span>
</span>

Fading Icon Indicator

You can use Material Icons from Google Fonts within your Fading Icon Indicator, or you can use your own icons.

<span class="mdc-tab-indicator mdc-tab-indicator--fade">
  <span class="mdc-tab-indicator__content mdc-tab-indicator__content--icon material-icons">star</span>
</span>

Sliding Icon Indicator

<span class="mdc-tab-indicator">
  <span class="mdc-tab-indicator__content mdc-tab-indicator__content--icon material-icons">star</span>
</span>

Style Customization

CSS Classes

CSS Class	Description
mdc-tab-indicator	Mandatory. Contains the tab indicator content.
mdc-tab-indicator__content	Mandatory. Denotes the tab indicator content.
mdc-tab-indicator--active	Optional. Visually activates the indicator.
mdc-tab-indicator--fade	Optional. Sets up the tab indicator to fade in on activation and fade out on deactivation.
mdc-tab-indicator__content--underline	Optional. Denotes an underline tab indicator.
mdc-tab-indicator__content--icon	Optional. Denotes an icon tab indicator.

NOTE: Exactly one of the --underline or --icon content modifier classes should be present.

Sass Mixins

To customize the tab indicator, use the following mixins.

Mixin	Description
mdc-tab-indicator-surface	Mandatory. Must be applied to the parent element of the mdc-tab-indicator.
mdc-tab-indicator-underline-color($color)	Customizes the color of the underline.
mdc-tab-indicator-icon-color($color)	Customizes the color of the icon subelement.
mdc-tab-indicator-underline-height($height)	Customizes the height of the underline.
mdc-tab-indicator-icon-height($height)	Customizes the height of the icon subelement.
mdc-tab-indicator-underline-top-corner-radius($radius)	Customizes the top left and top right border radius of the underline child element.

MDCTabIndicator Methods

Method Signature	Description
activate(previousIndicatorClientRect: ClientRect) => void	Activates the tab indicator.
deactivate() => void	Deactivates the tab indicator.
computeContentClientRect() => ClientRect	Returns the content element bounding client rect.

Usage within Web Frameworks

If you are using a JavaScript framework, such as React or Angular, you can create a Tab Indicator for your framework. Depending on your needs, you can use the Simple Approach: Wrapping MDC Web Vanilla Components, or the Advanced Approach: Using Foundations and Adapters. Please follow the instructions here.

MDCTabIndicatorAdapter

Method Signature	Description
addClass(className: string) => void	Adds a class to the root element.
removeClass(className: string) => void	Removes a class from the root element.
setContentStyleProp(property: string, value: string) => void	Sets the style property of the content element.
computeContentClientRect() => ClientRect	Returns the content element's bounding client rect.

MDCTabIndicatorFoundation

Method Signature	Description
handleTransitionEnd(evt: Event) => void	Handles the logic for the "transitionend" event on the root element.
activate(previousIndicatorClientRect: ClientRect) => void	Activates the tab indicator.
deactivate() => void	Deactivates the tab indicator.
computeContentClientRect() => ClientRect	Returns the content element's bounding client rect.