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Closest node function to AstarFinder.js #127

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Closest node function to AstarFinder.js #127

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24 changes: 20 additions & 4 deletions src/finders/AStarFinder.js
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Original file line number Diff line number Diff line change
Expand Up @@ -24,6 +24,7 @@ function AStarFinder(opt) {
this.heuristic = opt.heuristic || Heuristic.manhattan;
this.weight = opt.weight || 1;
this.diagonalMovement = opt.diagonalMovement;
this.closest = opt.closest || false;

if (!this.diagonalMovement) {
if (!this.allowDiagonal) {
Expand Down Expand Up @@ -62,10 +63,15 @@ AStarFinder.prototype.findPath = function(startX, startY, endX, endY, grid) {
weight = this.weight,
abs = Math.abs, SQRT2 = Math.SQRT2,
node, neighbors, neighbor, i, l, x, y, ng;
closest = this.closest;

// set the `g` and `f` value of the start node to be 0
startNode.g = 0;
startNode.f = 0;
if(closest){
closestNode = startNode;
closestNode.h = heuristic(abs(startX - endX), abs(startY - endY));
}

// push the start node into the open list
openList.push(startNode);
Expand Down Expand Up @@ -105,7 +111,13 @@ AStarFinder.prototype.findPath = function(startX, startY, endX, endY, grid) {
neighbor.h = neighbor.h || weight * heuristic(abs(x - endX), abs(y - endY));
neighbor.f = neighbor.g + neighbor.h;
neighbor.parent = node;


// if the neighbour is closer than the current closestNode or if it's equally close but has
// a cheaper path than the current closest node then it becomes the closest node
if (closest && (neighbor.h < closestNode.h || (neighbor.h === closestNode.h && neighbor.g < closestNode.g))) {
closestNode = neighbor;
}

if (!neighbor.opened) {
openList.push(neighbor);
neighbor.opened = true;
Expand All @@ -118,9 +130,13 @@ AStarFinder.prototype.findPath = function(startX, startY, endX, endY, grid) {
}
} // end for each neighbor
} // end while not open list empty

// fail to find the path
return [];

// if end position not reached, return closest open node
if(closest)
return Util.backtrace(closestNode);

// fail to find the path
return [];
};

module.exports = AStarFinder;