Merge pull request #2 from sethu1504/minor-first-direction-update

First time sort direction logic update and testing

Author: sethu1504

components/data-table/private/header-cell.jsx

@@ -25,10 +25,6 @@ import {
 	DATA_TABLE_COLUMN,
 } from '../../../utilities/constants';
 
-const defaultProps = {
-	firstSortDirection: 'asc'
-};
-
 /**
  * Used internally, renders each individual column heading.
  */
@@ -84,8 +80,6 @@ class DataTableHeaderCell extends React.Component {
 		width: PropTypes.string,
 	};
 
-	static defaultProps = defaultProps;
-
 	state = {
 		sortDirection: null,
 	};
@@ -104,10 +98,16 @@ class DataTableHeaderCell extends React.Component {
 	handleSort = (e) => {
 		const oldSortDirection =
 			this.props.sortDirection || this.state.sortDirection;
-		var sortDirection = this.props.firstSortDirection
-		if (oldSortDirection) {
-			sortDirection = oldSortDirection === 'asc' ? 'desc' : 'asc'
-		}
+		const sortDirection = (function(sortDirection, firstDirection) {
+			switch(sortDirection) {
+				case 'asc':
+					return 'desc'
+				case 'desc':
+					return 'asc'
+				case null:
+					return (firstDirection) ? firstDirection : 'asc'
+			}
+		})(oldSortDirection, this.props.firstSortDirection)
 		const data = {
 			property: this.props.property,
 			sortDirection,
@@ -127,7 +127,7 @@ class DataTableHeaderCell extends React.Component {
 		const { fixedHeader, isSorted, label, sortable, width } = this.props;
 
 		const labelType = typeof label;
-		const sortDirection = (!this.props.sortDirection && !this.state.sortDirection) ? this.props.firstSortDirection : (this.props.sortDirection || this.state.sortDirection);
+		const sortDirection = this.props.sortDirection || this.state.sortDirection || this.props.firstSortDirection
 		const expandedSortDirection =
 			sortDirection === 'desc' ? 'descending' : 'ascending';
 		const ariaSort = isSorted ? expandedSortDirection : 'none';
@@ -157,7 +157,7 @@ class DataTableHeaderCell extends React.Component {
 						name={sortDirection === 'desc' ? 'arrowdown' : 'arrowup'}
 						size="x-small"
 					/>
-					{(sortDirection && this.state.sortable) ? (
+					{sortDirection ? (
 						<span
 							className="slds-assistive-text"
 							aria-live="assertive"