Composable API

useGridLayout exposes the layout state and operations without rendering GridLayout or GridItem. It is useful when you want to keep the placement rules but render your own markup.

Try it: Add, move, and remove items. The custom rendering reads every change from the headless layout state.

Live demo

Vue SFC

<script setup lang="ts">
import { ref } from 'vue'

import { useGridLayout } from 'grid-layout-plus'

import type { Layout } from 'grid-layout-plus'

const sourceLayout = ref<Layout>([
  { x: 0, y: 0, w: 2, h: 2, i: 'a' },
  { x: 2, y: 0, w: 2, h: 3, i: 'b' },
])

const { layout, addItem, moveItem, removeItem } = useGridLayout({
  layout: sourceLayout,
  cols: 6,
  rowHeight: 30,
  margin: [8, 8],
  containerPadding: [10, 10],
})

function add() {
  addItem({ x: 0, y: 0, w: 2, h: 2, i: `item-${layout.value.length}` })
}
</script>

<template>
  <button type="button" @click="add">
    <span>Add item</span>
  </button>
  <button type="button" @click="moveItem('a', 1, 0)">
    <span>Move item a</span>
  </button>
  <button type="button" @click="removeItem('b')">
    <span>Remove item b</span>
  </button>

  <pre>{{ layout }}</pre>
</template>

<script setup lang="ts">
import { computed, ref } from 'vue'

import { useContainerWidth, useGridLayout } from 'grid-layout-plus'

import type { Layout, LayoutOperationResult } from 'grid-layout-plus'

const cols = 6
const rowHeight = 30
const margin = [8, 8] as const
const containerPadding = [10, 10] as const

function createLayout(): Layout {
  return [
    { x: 0, y: 0, w: 2, h: 2, i: '0' },
    { x: 2, y: 0, w: 2, h: 3, i: '1' },
    { x: 4, y: 0, w: 2, h: 2, i: '2' },
    { x: 0, y: 3, w: 2, h: 2, i: '3' },
  ]
}

const containerRef = ref<HTMLElement | null>(null)
const { width } = useContainerWidth(containerRef)
const sourceLayout = ref<Layout>(createLayout())
const lastOperation = ref('None')

const { layout, containerHeight, moveItem, addItem, removeItem, setLayout } = useGridLayout({
  layout: sourceLayout,
  cols,
  rowHeight,
  margin,
  containerPadding,
})

let nextId = 4

function report(operation: string, result: LayoutOperationResult) {
  lastOperation.value =
    result.status === 'rejected'
      ? `${operation}: rejected (${result.reason})`
      : `${operation}: ${result.status}`
}

const cellWidth = computed(() => {
  if (width.value === null) return 0
  const available = width.value - containerPadding[0] * 2 - margin[0] * Math.max(0, cols - 1)
  return Math.max(0, available / cols)
})

function getItemStyle(item: Layout[number]) {
  const itemWidth = item.w * cellWidth.value + Math.max(0, item.w - 1) * margin[0]
  const itemHeight = item.h * rowHeight + Math.max(0, item.h - 1) * margin[1]
  const left = containerPadding[0] + item.x * (cellWidth.value + margin[0])
  const top = containerPadding[1] + item.y * (rowHeight + margin[1])
  return {
    width: `${itemWidth}px`,
    height: `${itemHeight}px`,
    transform: `translate3d(${left}px, ${top}px, 0)`,
  }
}

function handleAdd() {
  report('add', addItem({ x: 0, y: 0, w: 2, h: 2, i: String(nextId++) }))
}

function handleMoveFirst() {
  const item = layout.value[0]
  if (item) {
    report('move', moveItem(item.i, (item.x + 1) % (cols - item.w + 1), item.y))
  }
}

function handleRemoveLast() {
  const items = layout.value
  if (items.length > 0) {
    report('remove', removeItem(items[items.length - 1].i))
  }
}

function resetDemo() {
  report('reset', setLayout(createLayout()))
  nextId = 4
}
</script>

<template>
  <section class="demo-root demo-shell">
    <div class="demo-toolbar">
      <Button button-type="button" type="primary" @click="handleAdd">Add item</Button>
      <Button button-type="button" :disabled="!layout.length" @click="handleMoveFirst">
        Move first
      </Button>
      <Button
        button-type="button"
        type="error"
        :disabled="!layout.length"
        @click="handleRemoveLast"
      >
        Remove last
      </Button>
      <Button button-type="button" @click="resetDemo">Reset demo</Button>
    </div>
    <dl class="demo-metrics">
      <div class="demo-metric">
        <dt>Container</dt>
        <dd>{{ width === null ? 'measuring' : `${Math.round(width)}px` }}</dd>
      </div>
      <div class="demo-metric">
        <dt>Items</dt>
        <dd>{{ layout.length }}</dd>
      </div>
      <div class="demo-metric">
        <dt>Columns</dt>
        <dd>{{ cols }}</dd>
      </div>
      <div class="demo-metric">
        <dt>Last result</dt>
        <dd>{{ lastOperation }}</dd>
      </div>
    </dl>
    <div ref="containerRef" class="headless-grid" :style="{ height: `${containerHeight}px` }">
      <div v-for="item in layout" :key="item.i" class="headless-item" :style="getItemStyle(item)">
        <span>{{ item.i }}</span>
        <small>{{ item.x }},{{ item.y }} · {{ item.w }}×{{ item.h }}</small>
      </div>
      <p v-if="!layout.length" class="demo-empty">No items yet</p>
    </div>
  </section>
</template>

<style scoped>
.headless-grid {
  position: relative;
  min-height: 100px;
  overflow: hidden;
  background: var(--demo-canvas);
  border: 1px solid var(--demo-border-subtle);
  border-radius: 8px;
}

.headless-item {
  position: absolute;
  top: 0;
  left: 0;
  display: grid;
  align-content: center;
  color: var(--demo-text);
  text-align: center;
  background: var(--demo-item);
  border: 1px solid var(--demo-border);
  transition: transform 160ms ease;
}

.headless-item small {
  color: var(--demo-muted);
}
</style>