feat(tab-bar): Add component (#229)

package.json

@@ -58,7 +58,9 @@
     "@material/select": "^0.39.0",
     "@material/switch": "^0.39.0",
     "@material/tab": "^0.39.0",
+    "@material/tab-bar": "^0.39.0",
     "@material/tab-indicator": "^0.39.0",
+    "@material/tab-scroller": "^0.39.0",
     "@material/textfield": "^0.39.0",
     "@material/top-app-bar": "^0.39.0",
     "@material/typography": "^0.39.0",

packages/tab-bar/.npmignore

@@ -0,0 +1 @@
+index.js

packages/tab-bar/README.md

@@ -0,0 +1,70 @@
+# React Tab Bar
+
+A React version of an [MDC Tab Bar](https://github.com/material-components/material-components-web/tree/master/packages/mdc-tab-bar).
+
+## Installation
+
+```
+npm install @material/react-tab-bar
+```
+
+## Usage
+
+### Styles
+
+with Sass:
+```scss
+import '@material/react-tab-bar/index.scss';
+```
+
+with CSS:
+```css
+import '@material/react-tab-bar/dist/tab-bar.css';
+```
+
+### Javascript Instantiation
+
+```js
+import React from 'react';
+import Tab from '@material/react-tab';
+import TabBar from '@material/react-tab-bar';
+
+class MyApp extends React.Component {
+  state = {activeIndex: 0};
+
+  render() {
+    return (
+      <div>
+        <TabBar 
+          activeIndex={this.state.activeIndex}
+          handleActiveIndexUpdate={(activeIndex) => this.setState({activeIndex})}
+        >
+          <Tab>
+            <span className='mdc-tab__text-label'>One</span>
+          </Tab>
+          ...
+        </TabBar>
+      </div>
+    );
+  }
+}
+```
+
+> _NOTE_: You can also use a custom tab component with the `TabBar`, but it must implement the methods `activate`, `deactivate`, `focus`, `computeIndicatorClientRect`, and `computeDimensions`. See [`MDCTab` documentation](https://github.com/material-components/material-components-web/blob/master/packages/mdc-tab/README.md#mdctab-properties-and-methods) for more details.
+
+## Props
+
+Prop Name | Type | Description
+--- | --- | ---
+activeIndex | number | Index of the active tab.
+indexInView | number | Index of the tab to be scrolled into view.
+handleActiveIndexUpdate | Function(activeIndex: number) => void | Callback after the active index is updated.
+className | string | Classes to appear on className attribute of root element.
+isRtl | Boolean |  Whether the direction of the tab bar is RTL.
+
+## Sass Mixins
+
+Sass mixins may be available to customize various aspects of the components. Please refer to the
+MDC Web repository for more information on what mixins are available, and how to use them.
+
+[Advanced Sass Mixins](https://github.com/material-components/material-components-web/blob/master/packages/mdc-tab-bar/README.md#sass-mixins)

packages/tab-bar/index.js

@@ -0,0 +1,165 @@
+import React, {Component} from 'react';
+import PropTypes from 'prop-types';
+import classnames from 'classnames';
+
+import TabScroller from '@material/react-tab-scroller';
+import {MDCTabBarFoundation} from '@material/tab-bar/dist/mdc.tabBar';
+
+export default class TabBar extends Component {
+  tabBarElement_ = React.createRef();
+  tabScroller_ = React.createRef();
+  tabList_ = [];
+
+  foundation_ = null;
+  state = {
+    previousActiveIndex: -1,
+  }
+
+  componentDidMount() {
+    this.foundation_ = new MDCTabBarFoundation(this.adapter);
+    this.foundation_.init();
+
+    const {
+      activeIndex,
+      indexInView,
+    } = this.props;
+    if (this.tabList_[activeIndex]) {
+      this.tabList_[activeIndex].activate({} /* previousIndicatorClientRect */);
+    }
+    this.foundation_.scrollIntoView(indexInView);
+  }
+
+  componentDidUpdate(prevProps) {
+    if (this.props.activeIndex !== prevProps.activeIndex) {
+      this.foundation_.activateTab(this.props.activeIndex);
+    }
+    if (this.props.indexInView !== prevProps.indexInView) {
+      this.foundation_.scrollIntoView(this.props.indexInView);
+    }
+  }
+
+  componentWillUnmount() {
+    this.foundation_.destroy();
+  }
+
+  get classes() {
+    return classnames('mdc-tab-bar', this.props.className);
+  }
+
+  get adapter() {
+    return {
+      scrollTo: (scrollX) => this.tabScroller_.current.scrollTo(scrollX),
+      incrementScroll: (scrollXIncrement) => this.tabScroller_.current.incrementScroll(scrollXIncrement),
+      getScrollPosition: () => this.tabScroller_.current.getScrollPosition(),
+      getScrollContentWidth: () => this.tabScroller_.current.getScrollContentWidth(),
+      getOffsetWidth: () => this.tabBarElement_.current.offsetWidth,
+      isRTL: () => !!this.props.isRtl,
+      setActiveTab: (index) => this.props.handleActiveIndexUpdate(index),
+      activateTabAtIndex: (index, clientRect) => this.tabList_[index].activate(clientRect),
+      deactivateTabAtIndex: (index) => this.tabList_[index].deactivate(),
+      focusTabAtIndex: (index) => this.tabList_[index].focus(),
+      getTabIndicatorClientRectAtIndex: (index) => this.tabList_[index].computeIndicatorClientRect(),
+      getTabDimensionsAtIndex: (index) => this.tabList_[index].computeDimensions(),
+      getPreviousActiveTabIndex: () => this.state.previousActiveIndex,
+      getFocusedTabIndex: () => {
+        const activeElement = document.activeElement;
+        this.tabList_.forEach((tabList, index) => {
+          if (tabList.tabElement_.current === activeElement) {
+            return index;
+          }
+        });
+      },
+      getIndexOfTab: (tabToFind) => this.tabList_.indexOf(tabToFind),
+      getTabListLength: () => this.tabList_.length,
+    };
+  }
+
+  pushToTabList = (el) => {
+    this.tabList_.push(el);
+  }
+
+  onKeyDown = (e) => {
+    // Persist the synthetic event to access its `key`.
+    e.persist();
+    this.setState(
+      {previousActiveIndex: this.props.activeIndex},
+      () => this.foundation_.handleKeyDown(e));
+    this.props.onKeyDown(e);
+  }
+
+  render() {
+    const {
+      /* eslint-disable no-unused-vars */
+      className,
+      indexInView,
+      activeIndex,
+      handleActiveIndexUpdate,
+      onKeyDown,
+      /* eslint-enable no-unused-vars */
+      isRtl,
+      children,
+      ...otherProps
+    } = this.props;
+
+    return (
+      <div
+        dir={isRtl ? 'rtl' : 'ltr'}
+        className={this.classes}
+        role='tablist'
+        onKeyDown={this.onKeyDown}
+        ref={this.tabBarElement_}
+        {...otherProps}
+      >
+        <TabScroller ref={this.tabScroller_}>
+          {React.Children.map(children, this.renderTab)}
+        </TabScroller>
+      </div>
+    );
+  }
+
+  renderTab = (tab, index) => {
+    const {
+      children,
+      onClick, // eslint-disable-line no-unused-vars
+      ...otherProps
+    } = tab.props;
+
+    const props = {
+      onClick: (e) => {
+        this.setState(
+          {previousActiveIndex: this.props.activeIndex},
+          () => this.adapter.setActiveTab(index));
+        this.props.onClick(e);
+      },
+      ref: this.pushToTabList,
+      ...otherProps,
+    };
+
+    return React.cloneElement(tab, props, children);
+  }
+}
+
+TabBar.propTypes = {
+  indexInView: PropTypes.number,
+  activeIndex: PropTypes.number,
+  handleActiveIndexUpdate: PropTypes.func,
+  className: PropTypes.string,
+  children: PropTypes.oneOfType([
+    PropTypes.arrayOf(PropTypes.element),
+    PropTypes.element,
+  ]),
+  onClick: PropTypes.func,
+  onKeyDown: PropTypes.func,
+  isRtl: PropTypes.bool,
+};
+
+TabBar.defaultProps = {
+  indexInView: 0,
+  activeIndex: 0,
+  handleActiveIndexUpdate: () => {},
+  className: '',
+  children: [],
+  onClick: () => {},
+  onKeyDown: () => {},
+  isRtl: false,
+};

packages/tab-bar/index.scss

@@ -0,0 +1 @@
+@import "@material/tab-bar/mdc-tab-bar";

packages/tab-bar/package.json

@@ -0,0 +1,29 @@
+{
+  "name": "@material/react-tab-bar",
+  "version": "0.0.0",
+  "description": "Material Components React Tab Bar",
+  "license": "Apache-2.0",
+  "main": "dist/index.js",
+  "keywords": [
+    "mdc web react",
+    "material components react",
+    "material design",
+    "tab bar",
+    "tabbar",
+    "tabs"
+  ],
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/material-components/material-components-web-react.git"
+  },
+  "dependencies": {
+    "@material/react-tab-scroller": "^0.0.0",
+    "@material/tab-bar": "^0.39.0",
+    "classnames": "^2.2.5",
+    "prop-types": "^15.6.1",
+    "react": "^16.3.2"
+  },
+  "publishConfig": {
+    "access": "public"
+  }
+}