@jalez/react-flow-smart-edge/src/functions/guaranteeWalkablePath.ts

Smart edge routing for @xyflow/react v12+ (maintained fork of @tisoap/react-flow-smart-edge)

import type { Position, XYPosition } from '@xyflow/react'
import type { Grid } from 'pathfinding'

type Direction = 'top' | 'bottom' | 'left' | 'right'

export const getNextPointFromPosition = (
	point: XYPosition,
	position: Direction
): XYPosition => {
	switch (position) {
		case 'top':
			return { x: point.x, y: point.y - 1 }
		case 'bottom':
			return { x: point.x, y: point.y + 1 }
		case 'left':
			return { x: point.x - 1, y: point.y }
		case 'right':
			return { x: point.x + 1, y: point.y }
	}
}

/**
 * Guarantee that the path is walkable, even if the point is inside a non
 * walkable area, by adding a walkable path in the direction of the point's
 * Position.
 */
export const guaranteeWalkablePath = (
	grid: Grid,
	point: XYPosition,
	position: Position
) => {
	let node = grid.getNodeAt(point.x, point.y)
	while (!node.walkable) {
		grid.setWalkableAt(node.x, node.y, true)
		const next = getNextPointFromPosition(node, position)
		node = grid.getNodeAt(next.x, next.y)
	}
}