react-virtualized/dist/es/ArrowKeyStepper/ArrowKeyStepper.js

React components for efficiently rendering large, scrollable lists and tabular data

import React, { Component, PropTypes } from 'react';
import shallowCompare from 'react-addons-shallow-compare';

/**
 * This HOC decorates a virtualized component and responds to arrow-key events by scrolling one row or column at a time.
 */

var ArrowKeyStepper = function (_Component) {
  babelHelpers.inherits(ArrowKeyStepper, _Component);

  function ArrowKeyStepper(props, context) {
    babelHelpers.classCallCheck(this, ArrowKeyStepper);

    var _this = babelHelpers.possibleConstructorReturn(this, Object.getPrototypeOf(ArrowKeyStepper).call(this, props, context));

    _this.state = {
      scrollToColumn: 0,
      scrollToRow: 0
    };

    _this._columnStartIndex = 0;
    _this._columnStopIndex = 0;
    _this._rowStartIndex = 0;
    _this._rowStopIndex = 0;

    _this._onKeyDown = _this._onKeyDown.bind(_this);
    _this._onSectionRendered = _this._onSectionRendered.bind(_this);
    return _this;
  }

  babelHelpers.createClass(ArrowKeyStepper, [{
    key: 'render',
    value: function render() {
      var _props = this.props;
      var className = _props.className;
      var children = _props.children;
      var _state = this.state;
      var scrollToColumn = _state.scrollToColumn;
      var scrollToRow = _state.scrollToRow;


      return React.createElement(
        'div',
        {
          className: className,
          onKeyDown: this._onKeyDown
        },
        children({
          onSectionRendered: this._onSectionRendered,
          scrollToColumn: scrollToColumn,
          scrollToRow: scrollToRow
        })
      );
    }
  }, {
    key: 'shouldComponentUpdate',
    value: function shouldComponentUpdate(nextProps, nextState) {
      return shallowCompare(this, nextProps, nextState);
    }
  }, {
    key: '_onKeyDown',
    value: function _onKeyDown(event) {
      var _props2 = this.props;
      var columnsCount = _props2.columnsCount;
      var rowsCount = _props2.rowsCount;

      // The above cases all prevent default event event behavior.
      // This is to keep the grid from scrolling after the snap-to update.

      switch (event.key) {
        case 'ArrowDown':
          event.preventDefault();
          this.setState({
            scrollToRow: Math.min(this._rowStopIndex + 1, rowsCount - 1)
          });
          break;
        case 'ArrowLeft':
          event.preventDefault();
          this.setState({
            scrollToColumn: Math.max(this._columnStartIndex - 1, 0)
          });
          break;
        case 'ArrowRight':
          event.preventDefault();
          this.setState({
            scrollToColumn: Math.min(this._columnStopIndex + 1, columnsCount - 1)
          });
          break;
        case 'ArrowUp':
          event.preventDefault();
          this.setState({
            scrollToRow: Math.max(this._rowStartIndex - 1, 0)
          });
          break;
      }
    }
  }, {
    key: '_onSectionRendered',
    value: function _onSectionRendered(_ref) {
      var columnStartIndex = _ref.columnStartIndex;
      var columnStopIndex = _ref.columnStopIndex;
      var rowStartIndex = _ref.rowStartIndex;
      var rowStopIndex = _ref.rowStopIndex;

      this._columnStartIndex = columnStartIndex;
      this._columnStopIndex = columnStopIndex;
      this._rowStartIndex = rowStartIndex;
      this._rowStopIndex = rowStopIndex;
    }
  }]);
  return ArrowKeyStepper;
}(Component);

ArrowKeyStepper.propTypes = {
  children: PropTypes.func.isRequired,
  className: PropTypes.string,
  columnsCount: PropTypes.number.isRequired,
  rowsCount: PropTypes.number.isRequired
};
export default ArrowKeyStepper;