gridstack
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TypeScript/JS lib for dashboard layout and creation, responsive, mobile support, no external dependencies, with many wrappers (React, Angular, Vue, Ember, knockout...)
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JavaScript
/**
* gridstack-engine.ts 12.4.1
* Copyright (c) 2021-2025 Alain Dumesny - see GridStack root license
*/
import { Utils } from './utils';
/**
* Defines the GridStack engine that handles all grid layout calculations and node positioning.
* This is the core engine that performs grid manipulation without any DOM operations.
*
* The engine manages:
* - Node positioning and collision detection
* - Layout algorithms (compact, float, etc.)
* - Grid resizing and column changes
* - Widget movement and resizing logic
*
* NOTE: Values should not be modified directly - use the main GridStack API instead
* to ensure proper DOM updates and event triggers.
*/
class GridStackEngine {
constructor(opts = {}) {
this.addedNodes = [];
this.removedNodes = [];
this.defaultColumn = 12;
this.column = opts.column || this.defaultColumn;
if (this.column > this.defaultColumn)
this.defaultColumn = this.column;
this.maxRow = opts.maxRow;
this._float = opts.float;
this.nodes = opts.nodes || [];
this.onChange = opts.onChange;
}
/**
* Enable/disable batch mode for multiple operations to optimize performance.
* When enabled, layout updates are deferred until batch mode is disabled.
*
* @param flag true to enable batch mode, false to disable and apply changes
* @param doPack if true (default), pack/compact nodes when disabling batch mode
* @returns the engine instance for chaining
*
* @example
* // Start batch mode for multiple operations
* engine.batchUpdate(true);
* engine.addNode(node1);
* engine.addNode(node2);
* engine.batchUpdate(false); // Apply all changes at once
*/
batchUpdate(flag = true, doPack = true) {
if (!!this.batchMode === flag)
return this;
this.batchMode = flag;
if (flag) {
this._prevFloat = this._float;
this._float = true; // let things go anywhere for now... will restore and possibly reposition later
this.cleanNodes();
this.saveInitial(); // since begin update (which is called multiple times) won't do this
}
else {
this._float = this._prevFloat;
delete this._prevFloat;
if (doPack)
this._packNodes();
this._notify();
}
return this;
}
// use entire row for hitting area (will use bottom reverse sorted first) if we not actively moving DOWN and didn't already skip
_useEntireRowArea(node, nn) {
return (!this.float || this.batchMode && !this._prevFloat) && !this._hasLocked && (!node._moving || node._skipDown || nn.y <= node.y);
}
/** @internal fix collision on given 'node', going to given new location 'nn', with optional 'collide' node already found.
* return true if we moved. */
_fixCollisions(node, nn = node, collide, opt = {}) {
this.sortNodes(-1); // from last to first, so recursive collision move items in the right order
collide = collide || this.collide(node, nn); // REAL area collide for swap and skip if none...
if (!collide)
return false;
// swap check: if we're actively moving in gravity mode, see if we collide with an object the same size
if (node._moving && !opt.nested && !this.float) {
if (this.swap(node, collide))
return true;
}
// during while() collisions MAKE SURE to check entire row so larger items don't leap frog small ones (push them all down starting last in grid)
let area = nn;
if (!this._loading && this._useEntireRowArea(node, nn)) {
area = { x: 0, w: this.column, y: nn.y, h: nn.h };
collide = this.collide(node, area, opt.skip); // force new hit
}
let didMove = false;
const newOpt = { nested: true, pack: false };
let counter = 0;
while (collide = collide || this.collide(node, area, opt.skip)) { // could collide with more than 1 item... so repeat for each
if (counter++ > this.nodes.length * 2) {
throw new Error("Infinite collide check");
}
let moved;
// if colliding with a locked item OR loading (move after) OR moving down with top gravity (and collide could move up) -> skip past the collide,
// but remember that skip down so we only do this once (and push others otherwise).
if (collide.locked || this._loading || node._moving && !node._skipDown && nn.y > node.y && !this.float &&
// can take space we had, or before where we're going
(!this.collide(collide, { ...collide, y: node.y }, node) || !this.collide(collide, { ...collide, y: nn.y - collide.h }, node))) {
node._skipDown = (node._skipDown || nn.y > node.y);
const newNN = { ...nn, y: collide.y + collide.h, ...newOpt };
// pretent we moved to where we are now so we can continue any collision checks #2492
moved = this._loading && Utils.samePos(node, newNN) ? true : this.moveNode(node, newNN);
if ((collide.locked || this._loading) && moved) {
Utils.copyPos(nn, node); // moving after lock become our new desired location
}
else if (!collide.locked && moved && opt.pack) {
// we moved after and will pack: do it now and keep the original drop location, but past the old collide to see what else we might push way
this._packNodes();
nn.y = collide.y + collide.h;
Utils.copyPos(node, nn);
}
didMove = didMove || moved;
}
else {
// move collide down *after* where we will be, ignoring where we are now (don't collide with us)
moved = this.moveNode(collide, { ...collide, y: nn.y + nn.h, skip: node, ...newOpt });
}
if (!moved)
return didMove; // break inf loop if we couldn't move after all (ex: maxRow, fixed)
collide = undefined;
}
return didMove;
}
/**
* Return the first node that intercepts/collides with the given node or area.
* Used for collision detection during drag and drop operations.
*
* @param skip the node to skip in collision detection (usually the node being moved)
* @param area the area to check for collisions (defaults to skip node's area)
* @param skip2 optional second node to skip in collision detection
* @returns the first colliding node, or undefined if no collision
*
* @example
* const colliding = engine.collide(draggedNode, {x: 2, y: 1, w: 2, h: 1});
* if (colliding) {
* console.log('Would collide with:', colliding.id);
* }
*/
collide(skip, area = skip, skip2) {
const skipId = skip._id;
const skip2Id = skip2?._id;
return this.nodes.find(n => n._id !== skipId && n._id !== skip2Id && Utils.isIntercepted(n, area));
}
/**
* Return all nodes that intercept/collide with the given node or area.
* Similar to collide() but returns all colliding nodes instead of just the first.
*
* @param skip the node to skip in collision detection
* @param area the area to check for collisions (defaults to skip node's area)
* @param skip2 optional second node to skip in collision detection
* @returns array of all colliding nodes
*
* @example
* const allCollisions = engine.collideAll(draggedNode);
* console.log('Colliding with', allCollisions.length, 'nodes');
*/
collideAll(skip, area = skip, skip2) {
const skipId = skip._id;
const skip2Id = skip2?._id;
return this.nodes.filter(n => n._id !== skipId && n._id !== skip2Id && Utils.isIntercepted(n, area));
}
/** does a pixel coverage collision based on where we started, returning the node that has the most coverage that is >50% mid line */
directionCollideCoverage(node, o, collides) {
if (!o.rect || !node._rect)
return;
const r0 = node._rect; // where started
const r = { ...o.rect }; // where we are
// update dragged rect to show where it's coming from (above or below, etc...)
if (r.y > r0.y) {
r.h += r.y - r0.y;
r.y = r0.y;
}
else {
r.h += r0.y - r.y;
}
if (r.x > r0.x) {
r.w += r.x - r0.x;
r.x = r0.x;
}
else {
r.w += r0.x - r.x;
}
let collide;
let overMax = 0.5; // need >50%
for (let n of collides) {
if (n.locked || !n._rect) {
break;
}
const r2 = n._rect; // overlapping target
let yOver = Number.MAX_VALUE, xOver = Number.MAX_VALUE;
// depending on which side we started from, compute the overlap % of coverage
// (ex: from above/below we only compute the max horizontal line coverage)
if (r0.y < r2.y) { // from above
yOver = ((r.y + r.h) - r2.y) / r2.h;
}
else if (r0.y + r0.h > r2.y + r2.h) { // from below
yOver = ((r2.y + r2.h) - r.y) / r2.h;
}
if (r0.x < r2.x) { // from the left
xOver = ((r.x + r.w) - r2.x) / r2.w;
}
else if (r0.x + r0.w > r2.x + r2.w) { // from the right
xOver = ((r2.x + r2.w) - r.x) / r2.w;
}
const over = Math.min(xOver, yOver);
if (over > overMax) {
overMax = over;
collide = n;
}
}
o.collide = collide; // save it so we don't have to find it again
return collide;
}
/** does a pixel coverage returning the node that has the most coverage by area */
/*
protected collideCoverage(r: GridStackPosition, collides: GridStackNode[]): {collide: GridStackNode, over: number} {
const collide: GridStackNode;
const overMax = 0;
collides.forEach(n => {
if (n.locked || !n._rect) return;
const over = Utils.areaIntercept(r, n._rect);
if (over > overMax) {
overMax = over;
collide = n;
}
});
return {collide, over: overMax};
}
*/
/**
* Cache the pixel rectangles for all nodes used for collision detection during drag operations.
* This optimization converts grid coordinates to pixel coordinates for faster collision detection.
*
* @param w width of a single grid cell in pixels
* @param h height of a single grid cell in pixels
* @param top top margin/padding in pixels
* @param right right margin/padding in pixels
* @param bottom bottom margin/padding in pixels
* @param left left margin/padding in pixels
* @returns the engine instance for chaining
*
* @internal This is typically called by GridStack during resize events
*/
cacheRects(w, h, top, right, bottom, left) {
this.nodes.forEach(n => n._rect = {
y: n.y * h + top,
x: n.x * w + left,
w: n.w * w - left - right,
h: n.h * h - top - bottom
});
return this;
}
/**
* Attempt to swap the positions of two nodes if they meet swapping criteria.
* Nodes can swap if they are the same size or in the same column/row, not locked, and touching.
*
* @param a first node to swap
* @param b second node to swap
* @returns true if swap was successful, false if not possible, undefined if not applicable
*
* @example
* const swapped = engine.swap(nodeA, nodeB);
* if (swapped) {
* console.log('Nodes swapped successfully');
* }
*/
swap(a, b) {
if (!b || b.locked || !a || a.locked)
return false;
function _doSwap() {
const x = b.x, y = b.y;
b.x = a.x;
b.y = a.y; // b -> a position
if (a.h != b.h) {
a.x = x;
a.y = b.y + b.h; // a -> goes after b
}
else if (a.w != b.w) {
a.x = b.x + b.w;
a.y = y; // a -> goes after b
}
else {
a.x = x;
a.y = y; // a -> old b position
}
a._dirty = b._dirty = true;
return true;
}
let touching; // remember if we called it (vs undefined)
// same size and same row or column, and touching
if (a.w === b.w && a.h === b.h && (a.x === b.x || a.y === b.y) && (touching = Utils.isTouching(a, b)))
return _doSwap();
if (touching === false)
return; // IFF ran test and fail, bail out
// check for taking same columns (but different height) and touching
if (a.w === b.w && a.x === b.x && (touching || (touching = Utils.isTouching(a, b)))) {
if (b.y < a.y) {
const t = a;
a = b;
b = t;
} // swap a <-> b vars so a is first
return _doSwap();
}
if (touching === false)
return;
// check if taking same row (but different width) and touching
if (a.h === b.h && a.y === b.y && (touching || (touching = Utils.isTouching(a, b)))) {
if (b.x < a.x) {
const t = a;
a = b;
b = t;
} // swap a <-> b vars so a is first
return _doSwap();
}
return false;
}
/**
* Check if the specified rectangular area is empty (no nodes occupy any part of it).
*
* @param x the x coordinate (column) of the area to check
* @param y the y coordinate (row) of the area to check
* @param w the width in columns of the area to check
* @param h the height in rows of the area to check
* @returns true if the area is completely empty, false if any node overlaps
*
* @example
* if (engine.isAreaEmpty(2, 1, 3, 2)) {
* console.log('Area is available for placement');
* }
*/
isAreaEmpty(x, y, w, h) {
const nn = { x: x || 0, y: y || 0, w: w || 1, h: h || 1 };
return !this.collide(nn);
}
/**
* Re-layout grid items to reclaim any empty space.
* This optimizes the grid layout by moving items to fill gaps.
*
* @param layout layout algorithm to use:
* - 'compact' (default): find truly empty spaces, may reorder items
* - 'list': keep the sort order exactly the same, move items up sequentially
* @param doSort if true (default), sort nodes by position before compacting
* @returns the engine instance for chaining
*
* @example
* // Compact to fill empty spaces
* engine.compact();
*
* // Compact preserving item order
* engine.compact('list');
*/
compact(layout = 'compact', doSort = true) {
if (this.nodes.length === 0)
return this;
if (doSort)
this.sortNodes();
const wasBatch = this.batchMode;
if (!wasBatch)
this.batchUpdate();
const wasColumnResize = this._inColumnResize;
if (!wasColumnResize)
this._inColumnResize = true; // faster addNode()
const copyNodes = this.nodes;
this.nodes = []; // pretend we have no nodes to conflict layout to start with...
copyNodes.forEach((n, index, list) => {
let after;
if (!n.locked) {
n.autoPosition = true;
if (layout === 'list' && index)
after = list[index - 1];
}
this.addNode(n, false, after); // 'false' for add event trigger
});
if (!wasColumnResize)
delete this._inColumnResize;
if (!wasBatch)
this.batchUpdate(false);
return this;
}
/**
* Enable/disable floating widgets (default: `false`).
* When floating is enabled, widgets can move up to fill empty spaces.
* See [example](http://gridstackjs.com/demo/float.html)
*
* @param val true to enable floating, false to disable
*
* @example
* engine.float = true; // Enable floating
* engine.float = false; // Disable floating (default)
*/
set float(val) {
if (this._float === val)
return;
this._float = val || false;
if (!val) {
this._packNodes()._notify();
}
}
/**
* Get the current floating mode setting.
*
* @returns true if floating is enabled, false otherwise
*
* @example
* const isFloating = engine.float;
* console.log('Floating enabled:', isFloating);
*/
get float() { return this._float || false; }
/**
* Sort the nodes array from first to last, or reverse.
* This is called during collision/placement operations to enforce a specific order.
*
* @param dir sort direction: 1 for ascending (first to last), -1 for descending (last to first)
* @returns the engine instance for chaining
*
* @example
* engine.sortNodes(); // Sort ascending (default)
* engine.sortNodes(-1); // Sort descending
*/
sortNodes(dir = 1) {
this.nodes = Utils.sort(this.nodes, dir);
return this;
}
/** @internal called to top gravity pack the items back OR revert back to original Y positions when floating */
_packNodes() {
if (this.batchMode) {
return this;
}
this.sortNodes(); // first to last
if (this.float) {
// restore original Y pos
this.nodes.forEach(n => {
if (n._updating || n._orig === undefined || n.y === n._orig.y)
return;
let newY = n.y;
while (newY > n._orig.y) {
--newY;
const collide = this.collide(n, { x: n.x, y: newY, w: n.w, h: n.h });
if (!collide) {
n._dirty = true;
n.y = newY;
}
}
});
}
else {
// top gravity pack
this.nodes.forEach((n, i) => {
if (n.locked)
return;
while (n.y > 0) {
const newY = i === 0 ? 0 : n.y - 1;
const canBeMoved = i === 0 || !this.collide(n, { x: n.x, y: newY, w: n.w, h: n.h });
if (!canBeMoved)
break;
// Note: must be dirty (from last position) for GridStack::OnChange CB to update positions
// and move items back. The user 'change' CB should detect changes from the original
// starting position instead.
n._dirty = (n.y !== newY);
n.y = newY;
}
});
}
return this;
}
/**
* Prepare and validate a node's coordinates and values for the current grid.
* This ensures the node has valid position, size, and properties before being added to the grid.
*
* @param node the node to prepare and validate
* @param resizing if true, resize the node down if it's out of bounds; if false, move it to fit
* @returns the prepared node with valid coordinates
*
* @example
* const node = { w: 3, h: 2, content: 'Hello' };
* const prepared = engine.prepareNode(node);
* console.log('Node prepared at:', prepared.x, prepared.y);
*/
prepareNode(node, resizing) {
node._id = node._id ?? GridStackEngine._idSeq++;
// make sure USER supplied id are unique in our list, else assign a new one as it will create issues during load/update/etc...
const id = node.id;
if (id) {
let count = 1; // append nice _n rather than some random number
while (this.nodes.find(n => n.id === node.id && n !== node)) {
node.id = id + '_' + (count++);
}
}
// if we're missing position, have the grid position us automatically (before we set them to 0,0)
if (node.x === undefined || node.y === undefined || node.x === null || node.y === null) {
node.autoPosition = true;
}
// assign defaults for missing required fields
const defaults = { x: 0, y: 0, w: 1, h: 1 };
Utils.defaults(node, defaults);
if (!node.autoPosition) {
delete node.autoPosition;
}
if (!node.noResize) {
delete node.noResize;
}
if (!node.noMove) {
delete node.noMove;
}
Utils.sanitizeMinMax(node);
// check for NaN (in case messed up strings were passed. can't do parseInt() || defaults.x above as 0 is valid #)
if (typeof node.x == 'string') {
node.x = Number(node.x);
}
if (typeof node.y == 'string') {
node.y = Number(node.y);
}
if (typeof node.w == 'string') {
node.w = Number(node.w);
}
if (typeof node.h == 'string') {
node.h = Number(node.h);
}
if (isNaN(node.x)) {
node.x = defaults.x;
node.autoPosition = true;
}
if (isNaN(node.y)) {
node.y = defaults.y;
node.autoPosition = true;
}
if (isNaN(node.w)) {
node.w = defaults.w;
}
if (isNaN(node.h)) {
node.h = defaults.h;
}
this.nodeBoundFix(node, resizing);
return node;
}
/**
* Part 2 of preparing a node to fit inside the grid - validates and fixes coordinates and dimensions.
* This ensures the node fits within grid boundaries and respects min/max constraints.
*
* @param node the node to validate and fix
* @param resizing if true, resize the node to fit; if false, move the node to fit
* @returns the engine instance for chaining
*
* @example
* // Fix a node that might be out of bounds
* engine.nodeBoundFix(node, true); // Resize to fit
* engine.nodeBoundFix(node, false); // Move to fit
*/
nodeBoundFix(node, resizing) {
const before = node._orig || Utils.copyPos({}, node);
if (node.maxW) {
node.w = Math.min(node.w || 1, node.maxW);
}
if (node.maxH) {
node.h = Math.min(node.h || 1, node.maxH);
}
if (node.minW) {
node.w = Math.max(node.w || 1, node.minW);
}
if (node.minH) {
node.h = Math.max(node.h || 1, node.minH);
}
// if user loaded a larger than allowed widget for current # of columns,
// remember it's position & width so we can restore back (1 -> 12 column) #1655 #1985
// IFF we're not in the middle of column resizing!
const saveOrig = (node.x || 0) + (node.w || 1) > this.column;
if (saveOrig && this.column < this.defaultColumn && !this._inColumnResize && !this.skipCacheUpdate && node._id != null && this.findCacheLayout(node, this.defaultColumn) === -1) {
const copy = { ...node }; // need _id + positions
if (copy.autoPosition || copy.x === undefined) {
delete copy.x;
delete copy.y;
}
else
copy.x = Math.min(this.defaultColumn - 1, copy.x);
copy.w = Math.min(this.defaultColumn, copy.w || 1);
this.cacheOneLayout(copy, this.defaultColumn);
}
if (node.w > this.column) {
node.w = this.column;
}
else if (node.w < 1) {
node.w = 1;
}
if (this.maxRow && node.h > this.maxRow) {
node.h = this.maxRow;
}
else if (node.h < 1) {
node.h = 1;
}
if (node.x < 0) {
node.x = 0;
}
if (node.y < 0) {
node.y = 0;
}
if (node.x + node.w > this.column) {
if (resizing) {
node.w = this.column - node.x;
}
else {
node.x = this.column - node.w;
}
}
if (this.maxRow && node.y + node.h > this.maxRow) {
if (resizing) {
node.h = this.maxRow - node.y;
}
else {
node.y = this.maxRow - node.h;
}
}
if (!Utils.samePos(node, before)) {
node._dirty = true;
}
return this;
}
/**
* Returns a list of nodes that have been modified from their original values.
* This is used to track which nodes need DOM updates.
*
* @param verify if true, performs additional verification by comparing current vs original positions
* @returns array of nodes that have been modified
*
* @example
* const changed = engine.getDirtyNodes();
* console.log('Modified nodes:', changed.length);
*
* // Get verified dirty nodes
* const verified = engine.getDirtyNodes(true);
*/
getDirtyNodes(verify) {
// compare original x,y,w,h instead as _dirty can be a temporary state
if (verify) {
return this.nodes.filter(n => n._dirty && !Utils.samePos(n, n._orig));
}
return this.nodes.filter(n => n._dirty);
}
/** @internal call this to call onChange callback with dirty nodes so DOM can be updated */
_notify(removedNodes) {
if (this.batchMode || !this.onChange)
return this;
const dirtyNodes = (removedNodes || []).concat(this.getDirtyNodes());
this.onChange(dirtyNodes);
return this;
}
/**
* Clean all dirty and last tried information from nodes.
* This resets the dirty state tracking for all nodes.
*
* @returns the engine instance for chaining
*
* @internal
*/
cleanNodes() {
if (this.batchMode)
return this;
this.nodes.forEach(n => {
delete n._dirty;
delete n._lastTried;
});
return this;
}
/**
* Save the initial position/size of all nodes to track real dirty state.
* This creates a snapshot of current positions that can be restored later.
*
* Note: Should be called right after change events and before move/resize operations.
*
* @returns the engine instance for chaining
*
* @internal
*/
saveInitial() {
this.nodes.forEach(n => {
n._orig = Utils.copyPos({}, n);
delete n._dirty;
});
this._hasLocked = this.nodes.some(n => n.locked);
return this;
}
/**
* Restore all nodes back to their initial values.
* This is typically called when canceling an operation (e.g., Esc key during drag).
*
* @returns the engine instance for chaining
*
* @internal
*/
restoreInitial() {
this.nodes.forEach(n => {
if (!n._orig || Utils.samePos(n, n._orig))
return;
Utils.copyPos(n, n._orig);
n._dirty = true;
});
this._notify();
return this;
}
/**
* Find the first available empty spot for the given node dimensions.
* Updates the node's x,y attributes with the found position.
*
* @param node the node to find a position for (w,h must be set)
* @param nodeList optional list of nodes to check against (defaults to engine nodes)
* @param column optional column count (defaults to engine column count)
* @param after optional node to start search after (maintains order)
* @returns true if an empty position was found and node was updated
*
* @example
* const node = { w: 2, h: 1 };
* if (engine.findEmptyPosition(node)) {
* console.log('Found position at:', node.x, node.y);
* }
*/
findEmptyPosition(node, nodeList = this.nodes, column = this.column, after) {
const start = after ? after.y * column + (after.x + after.w) : 0;
let found = false;
for (let i = start; !found; ++i) {
const x = i % column;
const y = Math.floor(i / column);
if (x + node.w > column) {
continue;
}
const box = { x, y, w: node.w, h: node.h };
if (!nodeList.find(n => Utils.isIntercepted(box, n))) {
if (node.x !== x || node.y !== y)
node._dirty = true;
node.x = x;
node.y = y;
delete node.autoPosition;
found = true;
}
}
return found;
}
/**
* Add the given node to the grid, handling collision detection and re-packing.
* This is the main method for adding new widgets to the engine.
*
* @param node the node to add to the grid
* @param triggerAddEvent if true, adds node to addedNodes list for event triggering
* @param after optional node to place this node after (for ordering)
* @returns the added node (or existing node if duplicate)
*
* @example
* const node = { x: 0, y: 0, w: 2, h: 1, content: 'Hello' };
* const added = engine.addNode(node, true);
*/
addNode(node, triggerAddEvent = false, after) {
const dup = this.nodes.find(n => n._id === node._id);
if (dup)
return dup; // prevent inserting twice! return it instead.
// skip prepareNode if we're in middle of column resize (not new) but do check for bounds!
this._inColumnResize ? this.nodeBoundFix(node) : this.prepareNode(node);
delete node._temporaryRemoved;
delete node._removeDOM;
let skipCollision;
if (node.autoPosition && this.findEmptyPosition(node, this.nodes, this.column, after)) {
delete node.autoPosition; // found our slot
skipCollision = true;
}
this.nodes.push(node);
if (triggerAddEvent) {
this.addedNodes.push(node);
}
if (!skipCollision)
this._fixCollisions(node);
if (!this.batchMode) {
this._packNodes()._notify();
}
return node;
}
/**
* Remove the given node from the grid.
*
* @param node the node to remove
* @param removeDOM if true (default), marks node for DOM removal
* @param triggerEvent if true, adds node to removedNodes list for event triggering
* @returns the engine instance for chaining
*
* @example
* engine.removeNode(node, true, true);
*/
removeNode(node, removeDOM = true, triggerEvent = false) {
if (!this.nodes.find(n => n._id === node._id)) {
// TEST console.log(`Error: GridStackEngine.removeNode() node._id=${node._id} not found!`)
return this;
}
if (triggerEvent) { // we wait until final drop to manually track removed items (rather than during drag)
this.removedNodes.push(node);
}
if (removeDOM)
node._removeDOM = true; // let CB remove actual HTML (used to set _id to null, but then we loose layout info)
// don't use 'faster' .splice(findIndex(),1) in case node isn't in our list, or in multiple times.
this.nodes = this.nodes.filter(n => n._id !== node._id);
if (!node._isAboutToRemove)
this._packNodes(); // if dragged out, no need to relayout as already done...
this._notify([node]);
return this;
}
/**
* Remove all nodes from the grid.
*
* @param removeDOM if true (default), marks all nodes for DOM removal
* @param triggerEvent if true (default), triggers removal events
* @returns the engine instance for chaining
*
* @example
* engine.removeAll(); // Remove all nodes
*/
removeAll(removeDOM = true, triggerEvent = true) {
delete this._layouts;
if (!this.nodes.length)
return this;
removeDOM && this.nodes.forEach(n => n._removeDOM = true); // let CB remove actual HTML (used to set _id to null, but then we loose layout info)
const removedNodes = this.nodes;
this.removedNodes = triggerEvent ? removedNodes : [];
this.nodes = [];
return this._notify(removedNodes);
}
/**
* Check if a node can be moved to a new position, considering layout constraints.
* This is a safer version of moveNode() that validates the move first.
*
* For complex cases (like maxRow constraints), it simulates the move in a clone first,
* then applies the changes only if they meet all specifications.
*
* @param node the node to move
* @param o move options including target position
* @returns true if the node was successfully moved
*
* @example
* const canMove = engine.moveNodeCheck(node, { x: 2, y: 1 });
* if (canMove) {
* console.log('Node moved successfully');
* }
*/
moveNodeCheck(node, o) {
// if (node.locked) return false;
if (!this.changedPosConstrain(node, o))
return false;
o.pack = true;
// simpler case: move item directly...
if (!this.maxRow) {
return this.moveNode(node, o);
}
// complex case: create a clone with NO maxRow (will check for out of bounds at the end)
let clonedNode;
const clone = new GridStackEngine({
column: this.column,
float: this.float,
nodes: this.nodes.map(n => {
if (n._id === node._id) {
clonedNode = { ...n };
return clonedNode;
}
return { ...n };
})
});
if (!clonedNode)
return false;
// check if we're covering 50% collision and could move, while still being under maxRow or at least not making it worse
// (case where widget was somehow added past our max #2449)
const canMove = clone.moveNode(clonedNode, o) && clone.getRow() <= Math.max(this.getRow(), this.maxRow);
// else check if we can force a swap (float=true, or different shapes) on non-resize
if (!canMove && !o.resizing && o.collide) {
const collide = o.collide.el.gridstackNode; // find the source node the clone collided with at 50%
if (this.swap(node, collide)) { // swaps and mark dirty
this._notify();
return true;
}
}
if (!canMove)
return false;
// if clone was able to move, copy those mods over to us now instead of caller trying to do this all over!
// Note: we can't use the list directly as elements and other parts point to actual node, so copy content
clone.nodes.filter(n => n._dirty).forEach(c => {
const n = this.nodes.find(a => a._id === c._id);
if (!n)
return;
Utils.copyPos(n, c);
n._dirty = true;
});
this._notify();
return true;
}
/** return true if can fit in grid height constrain only (always true if no maxRow) */
willItFit(node) {
delete node._willFitPos;
if (!this.maxRow)
return true;
// create a clone with NO maxRow and check if still within size
const clone = new GridStackEngine({
column: this.column,
float: this.float,
nodes: this.nodes.map(n => { return { ...n }; })
});
const n = { ...node }; // clone node so we don't mod any settings on it but have full autoPosition and min/max as well! #1687
this.cleanupNode(n);
delete n.el;
delete n._id;
delete n.content;
delete n.grid;
clone.addNode(n);
if (clone.getRow() <= this.maxRow) {
node._willFitPos = Utils.copyPos({}, n);
return true;
}
return false;
}
/** true if x,y or w,h are different after clamping to min/max */
changedPosConstrain(node, p) {
// first make sure w,h are set for caller
p.w = p.w || node.w;
p.h = p.h || node.h;
if (node.x !== p.x || node.y !== p.y)
return true;
// check constrained w,h
if (node.maxW) {
p.w = Math.min(p.w, node.maxW);
}
if (node.maxH) {
p.h = Math.min(p.h, node.maxH);
}
if (node.minW) {
p.w = Math.max(p.w, node.minW);
}
if (node.minH) {
p.h = Math.max(p.h, node.minH);
}
return (node.w !== p.w || node.h !== p.h);
}
/** return true if the passed in node was actually moved (checks for no-op and locked) */
moveNode(node, o) {
if (!node || /*node.locked ||*/ !o)
return false;
let wasUndefinedPack;
if (o.pack === undefined && !this.batchMode) {
wasUndefinedPack = o.pack = true;
}
// constrain the passed in values and check if we're still changing our node
if (typeof o.x !== 'number') {
o.x = node.x;
}
if (typeof o.y !== 'number') {
o.y = node.y;
}
if (typeof o.w !== 'number') {
o.w = node.w;
}
if (typeof o.h !== 'number') {
o.h = node.h;
}
const resizing = (node.w !== o.w || node.h !== o.h);
const nn = Utils.copyPos({}, node, true); // get min/max out first, then opt positions next
Utils.copyPos(nn, o);
this.nodeBoundFix(nn, resizing);
Utils.copyPos(o, nn);
if (!o.forceCollide && Utils.samePos(node, o))
return false;
const prevPos = Utils.copyPos({}, node);
// check if we will need to fix collision at our new location
const collides = this.collideAll(node, nn, o.skip);
let needToMove = true;
if (collides.length) {
const activeDrag = node._moving && !o.nested;
// check to make sure we actually collided over 50% surface area while dragging
let collide = activeDrag ? this.directionCollideCoverage(node, o, collides) : collides[0];
// if we're enabling creation of sub-grids on the fly, see if we're covering 80% of either one, if we didn't already do that
if (activeDrag && collide && node.grid?.opts?.subGridDynamic && !node.grid._isTemp) {
const over = Utils.areaIntercept(o.rect, collide._rect);
const a1 = Utils.area(o.rect);
const a2 = Utils.area(collide._rect);
const perc = over / (a1 < a2 ? a1 : a2);
if (perc > .8) {
collide.grid.makeSubGrid(collide.el, undefined, node);
collide = undefined;
}
}
if (collide) {
needToMove = !this._fixCollisions(node, nn, collide, o); // check if already moved...
}
else {
needToMove = false; // we didn't cover >50% for a move, skip...
if (wasUndefinedPack)
delete o.pack;
}
}
// now move (to the original ask vs the collision version which might differ) and repack things
if (needToMove && !Utils.samePos(node, nn)) {
node._dirty = true;
Utils.copyPos(node, nn);
}
if (o.pack) {
this._packNodes()
._notify();
}
return !Utils.samePos(node, prevPos); // pack might have moved things back
}
getRow() {
return this.nodes.reduce((row, n) => Math.max(row, n.y + n.h), 0);
}
beginUpdate(node) {
if (!node._updating) {
node._updating = true;
delete node._skipDown;
if (!this.batchMode)
this.saveInitial();
}
return this;
}
endUpdate() {
const n = this.nodes.find(n => n._updating);
if (n) {
delete n._updating;
delete n._skipDown;
}
return this;
}
/** saves a copy of the largest column layout (eg 12 even when rendering 1 column) so we don't loose orig layout, unless explicity column
* count to use is given. returning a list of widgets for serialization
* @param saveElement if true (default), the element will be saved to GridStackWidget.el field, else it will be removed.
* @param saveCB callback for each node -> widget, so application can insert additional data to be saved into the widget data structure.
* @param column if provided, the grid will be saved for the given column count (IFF we have matching internal saved layout, or current layout).
* Note: nested grids will ALWAYS save the container w to match overall layouts (parent + child) to be consistent.
*/
save(saveElement = true, saveCB, column) {
// use the highest layout for any saved info so we can have full detail on reload #1849
// unless we're given a column to match (always set for nested grids)
const len = this._layouts?.length || 0;
let layout;
if (len) {
if (column) {
if (column !== this.column)
layout = this._layouts[column];
}
else if (this.column !== len - 1) {
layout = this._layouts[len - 1];
}
}
const list = [];
this.sortNodes();
this.nodes.forEach(n => {
const wl = layout?.find(l => l._id === n._id);
// use layout info fields instead if set
const w = { ...n, ...(wl || {}) };
Utils.removeInternalForSave(w, !saveElement);
if (saveCB)
saveCB(n, w);
list.push(w);
});
return list;
}
/** @internal called whenever a node is added or moved - updates the cached layouts */
layoutsNodesChange(nodes) {
if (!this._layouts || this._inColumnResize)
return this;
// remove smaller layouts - we will re-generate those on the fly... larger ones need to update
this._layouts.forEach((layout, column) => {
if (!layout || column === this.column)
return this;
if (column < this.column) {
this._layouts[column] = undefined;
}
else {
// we save the original x,y,w (h isn't cached) to see what actually changed to propagate better.
// NOTE: we don't need to check against out of bound scaling/moving as that will be done when using those cache values. #1785
const ratio = column / this.column;
nodes.forEach(node => {
if (!node._orig)
return; // didn't change (newly added ?)
const n = layout.find(l => l._id === node._id);
if (!n)
return; // no cache for new nodes. Will use those values.
// Y changed, push down same amount
// TODO: detect doing item 'swaps' will help instead of move (especially in 1 column mode)
if (n.y >= 0 && node.y !== node._orig.y) {
n.y += (node.y - node._orig.y);
if (n.y < 0)
n.y = 0;
}
// X changed, scale from new position
if (node.x !== node._orig.x) {
n.x = Math.round(node.x * ratio);
if (n.x < 0)
n.x = 0;
}
// width changed, scale from new width
if (node.w !== node._orig.w) {
n.w = Math.round(node.w * ratio);
if (n.w < 1)
n.w = 1;
}
// ...height always carries over from cache
});
}
});
return this;
}
/**
* @internal Called to scale the widget width & position up/down based on the column change.
* Note we store previous layouts (especially original ones) to make it possible to go
* from say 12 -> 1 -> 12 and get back to where we were.
*
* @param prevColumn previous number of columns
* @param column new column number
* @param layout specify the type of re-layout that will happen (position, size, etc...).
* Note: items will never be outside of the current column boundaries. default (moveScale). Ignored for 1 column
*/
columnChanged(prevColumn, column, layout = 'moveScale') {
if (!this.nodes.length || !column || prevColumn === column)
return this;
// simpler shortcuts layouts
const doCompact = layout === 'compact' || layout === 'list';
if (doCompact) {
this.sortNodes(1); // sort with original layout once and only once (new column will affect order otherwise)
}
// cache the current layout in case they want to go back (like 12 -> 1 -> 12) as it requires original data IFF we're sizing down (see below)
if (column < prevColumn)
this.cacheLayout(this.nodes, prevColumn);
this.batchUpdate(); // do this EARLY as it will call saveInitial() so we can detect where we started for _dirty and collision
let newNodes = [];
let nodes = doCompact ? this.nodes : Utils.sort(this.nodes, -1); // current column reverse sorting so we can insert last to front (limit collision)
// see if we have cached previous layout IFF we are going up in size (restore) otherwise always
// generate next size down from where we are (looks more natural as you gradually size down).
if (column > prevColumn && this._layouts) {
const cacheNodes = this._layouts[column] || [];
// ...if not, start with the largest layout (if not already there) as down-scaling is more accurate
// by pretending we came from that larger column by assigning those values as starting point
const lastIndex = this._layouts.length - 1;
if (!cacheNodes.length && prevColumn !== lastIndex && this._layouts[lastIndex]?.length) {
prevColumn = lastIndex;
this._layouts[lastIndex].forEach(cacheNode => {
const n = nodes.find(n => n._id === cacheNode._id);
if (n) {
// still current, use cache info positions
if (!doCompact && !cacheNode.autoPosition) {
n.x = cacheNode.x ?? n.x;
n.y = cacheNode.y ?? n.y;
}
n.w = cacheNode.w ?? n.w;
if (cacheNode.x == undefined || cacheNode.y === undefined)
n.autoPosition = true;
}
});
}
// if we found cache re-use those nodes that are still current
cacheNodes.forEach(cacheNode => {
const j = nodes.findIndex(n => n._id === cacheNode._id);
if (j !== -1) {
const n = nodes[j];
// still current, use cache info positions
if (doCompact) {
n.w = cacheNode.w; // only w is used, and don't trim the list
return;
}
if (cacheNode.autoPosition || isNaN(cacheNode.x) || isNaN(cacheNode.y)) {
this.findEmptyPosition(cacheNode, newNodes);
}
if (!cacheNode.autoPosition) {
n.x = cacheNode.x ?? n.x;
n.y = cacheNode.y ?? n.y;
n.w = cacheNode.w ?? n.w;
newNodes.push(n);
}
nodes.splice(j, 1);
}
});
}
// much simpler layout that just compacts
if (doCompact) {
this.compact(layout, false);
}
else {
// ...and add any extra non-cached ones
if (nodes.length) {
if (typeof layout === 'function') {
layout(column, prevColumn, newNodes, nodes);
}
else {
const ratio = (doCompact || layout === 'none') ? 1 : column / prevColumn;
const move = (layout === 'move' || layout === 'moveScale');
const scale = (layout === 'scale' || layout === 'moveScale');
nodes.forEach(node => {
// NOTE: x + w could be outside of the grid, but addNode() below will handle that
node.x = (column === 1 ? 0 : (move ? Math.round(node.x * ratio) : Math.min(node.x, column - 1)));
node.w = ((column === 1 || prevColumn === 1) ? 1 : scale ? (Math.round(node.w * ratio) || 1) : (Math.min(node.w, column)));
newNodes.push(node);
});
nodes = [];
}
}
// finally re-layout them in reverse order (to get correct placement)
newNodes = Utils.sort(newNodes, -1);
this._inColumnResize = true; // prevent cache update
this.nodes = []; // pretend we have no nodes to start with (add() will use same structures) to simplify layout
newN