Compactors

Control how layouts pack and collide.

Compactors are pluggable strategies that determine how items pack when space opens up and how collisions are resolved. Pass a Compactor to the compactor prop on DndGrid, or use them with responsive layouts.

Built-in compactors

Compactor	Behavior
`verticalCompactor`	Default. Packs items upward by row.
`horizontalCompactor`	Packs items left-to-right, wrapping to the next row.
`noCompactor`	Leaves items where they are, no packing.
`verticalOverlapCompactor`	Vertical mode but allows overlap.
`horizontalOverlapCompactor`	Horizontal mode but allows overlap.
`fastVerticalCompactor`	Faster vertical packing for large layouts.
`fastHorizontalCompactor`	Faster horizontal packing for large layouts.
`fastVerticalOverlapCompactor`	Fast vertical mode with overlap allowed.
`fastHorizontalOverlapCompactor`	Fast horizontal mode with overlap allowed.

import {
  verticalCompactor,
  horizontalCompactor,
  noCompactor,
  fastVerticalCompactor,
} from "@dnd-grid/react";

<DndGrid compactor={verticalCompactor} />
<DndGrid compactor={horizontalCompactor} />
<DndGrid compactor={noCompactor} />
<DndGrid compactor={fastVerticalCompactor} />

Overlap and collision behavior

allowOverlap: true skips collision resolution. Items can overlap freely.
preventCollision: true blocks a move if it would collide with another item.

import { verticalCompactor, verticalOverlapCompactor } from "@dnd-grid/react";

<DndGrid compactor={{ ...verticalCompactor, preventCollision: true }} />
<DndGrid compactor={verticalOverlapCompactor} />

Helpers and custom compactors

A compactor has four fields: type, allowOverlap, compact, and onMove. You can implement your own, or build on the helpers below:

compactItemVertical
compactItemHorizontal
resolveCompactionCollision

import { type Compactor, compactItemVertical } from "@dnd-grid/react";

const myCompactor: Compactor = {
  type: "vertical",
  allowOverlap: false,
  compact(layout, _cols) {
    // Reorder items by your own logic, then compact vertically.
    const sorted = [...layout];
    const out = sorted.map((item) => ({ ...item }));
    const compareWith = out.filter((item) => item.static);
    let maxY = 0;

    for (const item of out) {
      if (!item.static) {
        compactItemVertical(compareWith, item, out, maxY);
        maxY = Math.max(maxY, item.y + item.h);
        compareWith.push(item);
      }
    }

    return out;
  },
  onMove(layout, item, x, y) {
    return layout.map((entry) =>
      entry.id === item.id ? { ...entry, x, y, moved: true } : entry,
    );
  },
};