Add column sort state.

src/Smartable/Column.tsx

@@ -1,4 +1,4 @@
-import React, {useContext} from "react";
+import React, {useCallback, useContext} from "react";
 import {Smartable, useTable} from "./Smartable";
 
 /**
@@ -48,6 +48,31 @@ export function createColumn<K extends ColumnKey>(key: K, column: Column): [K, C
 	return [key, column];
 }
 
+/**
+ * Column sort type.
+ */
+export enum SortType
+{
+	ASC = "asc",
+	DESC = "desc",
+}
+
+/**
+ * Column sort state.
+ */
+export interface SortState
+{
+	/**
+	 * Sort type (ascending or descending).
+	 */
+	type: SortType;
+
+	/**
+	 * Sort order.
+	 */
+	order: number;
+}
+
 /**
  * Table column context data.
  */
@@ -62,6 +87,11 @@ export interface ColumnContextData<CK extends ColumnKey>
 	 * Column definition.
 	 */
 	column: Column;
+
+	/**
+	 * Column sort state.
+	 */
+	sortState?: SortState;
 }
 
 export const ColumnContext = React.createContext<ColumnContextData<ColumnKey>>(undefined);
@@ -80,8 +110,37 @@ export function useColumn<CK extends ColumnKey>(smartable?: Smartable<CK>): Colu
 export function ColumnHeading()
 {
 	// Get current column data.
-	const {column} = useColumn();
-	return <th>{column.title}</th>;
+	const {key, column, sortState} = useColumn();
+
+	// Get column sort state setter.
+	const {setColumnSortState} = useTable();
+
+	// Initialize handle click function.
+	const handleClick = useCallback((event: React.MouseEvent) => {
+		if (event.button == 0)
+		{ // Normal click (usually left click).
+			// Toggle sort type.
+			setColumnSortState(key, sortState?.type == SortType.ASC ? SortType.DESC : SortType.ASC);
+		}
+		else if (event.button == 2 || event.button == 1)
+		{ // Alt click (usually right or middle click).
+			// Reset sort type.
+			setColumnSortState(key, null);
+		}
+	}, [key, sortState, setColumnSortState]);
+
+	// Disable context menu function.
+	const disableContextMenu = useCallback((event: React.MouseEvent) => {
+		event.preventDefault();
+		return false;
+	}, []);
+
+	return (
+		<th className={sortState?.type ?? undefined}
+		    onMouseDown={handleClick} onContextMenu={disableContextMenu}>
+			{column.title}
+		</th>
+	);
 }
 
 /**
@@ -97,6 +156,8 @@ export function AutoColumnContextProvider({columnKey, children}: React.PropsWith
 			key: columnKey,
 			// Get current column data from table data.
 			column: table.columns[columnKey],
+			// Get current column sort state from table data.
+			sortState: table.columnsSortState?.[columnKey],
 		}}>
 			{children}
 		</ColumnContext.Provider>

src/Smartable/Instance.tsx

@@ -1,5 +1,5 @@
 import React from "react";
-import {Column, ColumnContext, ColumnHeading, ColumnKey, Columns} from "./Column";
+import {AutoColumnContextProvider, Column, ColumnContext, ColumnHeading, ColumnKey, Columns} from "./Column";
 import {SmartableProperties, useTable} from "./Smartable";
 import {Async, Promisable} from "@kernelui/core";
 import {RowDefinition, RowInstance} from "./Row";
@@ -40,13 +40,10 @@ export function ColumnsHeadings<CK extends ColumnKey>({columns}: {columns: Colum
 	return (
 		<tr className={"headings"}>
 			{ // Showing title of each column.
-				Object.entries(columns).map(([key, column]) => (
-					<ColumnContext.Provider key={key} value={{
-						key: key,
-						column: column as Column,
-					}}>
+				Object.keys(columns).map((key) => (
+					<AutoColumnContextProvider key={key} columnKey={key}>
 						<ColumnHeading />
-					</ColumnContext.Provider>
+					</AutoColumnContextProvider>
 				))
 			}
 		</tr>

src/Smartable/Smartable.tsx

@@ -1,6 +1,6 @@
-import React, {useContext} from "react";
+import React, {useCallback, useContext, useMemo, useState} from "react";
 import {Instance} from "./Instance";
-import {ColumnKey, Columns} from "./Column";
+import {ColumnKey, Columns, SortState, SortType} from "./Column";
 import {RowDefinition} from "./Row";
 import {Promisable} from "@kernelui/core";
 
@@ -80,14 +80,54 @@ export function createSmartable<CK extends ColumnKey>({columns}: {
 
 	return {
 		Table: (props: SmartableProperties<CK>) => {
+			// Initialize sort state.
+			const [sortState, setSortState] = useState({} as Record<CK, SortState>);
+
 			// Filter columns from the given property.
 			const filteredColumns = props.shownColumns ? filterColumns(columns, props.shownColumns) : columns;
 
-			return (
-				<TableContext.Provider value={{
+			// Set sort state of a specific column.
+			const setColumnSortState = useCallback((key: CK, sortType: SortType|null): void => {
+				// Copy current sort state.
+				let newSortState = {...sortState};
+
+				if (sortType)
+					// A new sort type for given column has been set.
+					newSortState[key] = {
+						// Setting new sort type.
+						type: sortType,
+						// Keeping current order, or creating a new one (from the current state size).
+						order: newSortState?.[key]?.order ?? (Object.keys(sortState).length + 1),
+					};
+				else if (newSortState[key])
+				{ // Sort type for given column has been reset, removing it.
+					const removedOrderKey = newSortState[key]?.order;
+					delete newSortState[key];
+
+					// Decrement all remaining greater orders by one, as there is now one less sorted column.
+					newSortState = Object.fromEntries((Object.entries(newSortState) as [CK, SortState][]).map(
+						// For each column sort state...
+						([columnKey, {order: columnSortOrder, ...columnSortState}]) => (
+							//... copy the current column sort state, just decrement its order.
+							[columnKey, {order: columnSortOrder - (removedOrderKey < columnSortOrder ? 1 : 0), ...columnSortState} as SortState]
+						)
+					)) as Record<CK, SortState>;
+				}
+
+				// Set new sort state.
+				setSortState(newSortState);
+			}, [sortState, setSortState]);
+
+			// Initialize table context value.
+			const contextValue = useMemo<TableContextData<CK>>(() => ({
 				columns: filteredColumns,
+				columnsSortState: sortState,
+				setColumnSortState: setColumnSortState,
 				...props,
-				}}>
+			}), [filteredColumns, sortState, setSortState, props]);
+
+			return (
+				<TableContext.Provider value={contextValue}>
 					<Instance columns={filteredColumns} {...props} />
 				</TableContext.Provider>
 			);
@@ -105,6 +145,18 @@ export interface TableContextData<CK extends ColumnKey> extends SmartablePropert
 	 * Current table columns.
 	 */
 	columns: Columns<CK>;
+
+	/**
+	 * Current table columns sort state.
+	 */
+	columnsSortState: Record<CK, SortState>;
+
+	/**
+	 * Set current table columns sort state.
+	 * @param key The column key for which to set the sort type.
+	 * @param sortType The sort type to set for the given column. NULL to reset sort state.
+	 */
+	setColumnSortState: (key: CK, sortType: SortType|null) => void;
 }
 
 /**

src/styles/_headings.less

@@ -0,0 +1,64 @@
+tr.headings
+{
+	th
+	{
+		position: relative;
+
+		cursor: pointer;
+
+		&::before, &::after
+		{ // Sorting order indicator.
+			transition: height 0.2s ease, background 0.2s ease, top 0.2s ease, bottom 0.2s ease;
+
+			content: "";
+			position: absolute;
+			top: 0;
+			bottom: 0;
+
+			display: block;
+			margin: auto;
+			box-sizing: border-box;
+
+			background: var(--background-darkest);
+		}
+
+		&::before
+		{
+			right: calc(0.33em - 1px);
+
+			width: 2px;
+			height: 0;
+			border-radius: 2px;
+		}
+		&::after
+		{
+			right: calc(0.33em - 3px);
+
+			width: 6px;
+			height: 6px;
+			border-radius: 6px;
+		}
+
+		&.asc, &.desc
+		{
+			&::after, &::before
+			{
+				background: var(--primary);
+			}
+
+			&::before
+			{
+				height: 0.8em;
+			}
+		}
+
+		&.asc::after
+		{
+			top: 0.5em;
+		}
+		&.desc::after
+		{
+			bottom: 0.5em;
+		}
+	}
+}

src/styles/smartable.less

@@ -0,0 +1 @@
+@import "_headings";