基于 CSS Grid 的简易拖拉拽 Vue3 组件，从代码到NPM发布（1）- 拖拉拽交互

基于特定的应用场景，需要在页面中以网格的方式，实现目标组件在网格中可以进行拖拉拽、修改大小等交互。本章开始分享如何一步步从代码设计，最后到如何在 NPM 上发布。

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github源码

示例地址

特别说明一下，此组件是基于 CSS 的 display: grid 的，并非全能型拖拉拽交互，grid 不支持的基本就是不支持的，此组件的目标是达到一些简易的网格布局拖拉拽交互。

效果图

在这里插入图片描述

项目结构

项目结构是基于另外一个项目 konva-designer-sample，特别说一下需要关注的部分：

└─ dist - 构建的组件库文件
└─ docs - 构建的在线示例网站
└─ src
    └─ demo
    │   └─ App.vue - 在线示例页面
    └─ lib
        └─ components
            └─ GridDragResize - 组件目录
                └─ GridDragResize.vue - 组件
                └─ GridDragResizeItem.vue - 子组件
                └─ index.ts - 组件入口
                └─ style.less - 组件样式
                └─ types.ts - 组件配套类型声明
   └─ main.ts - 在线示例代码入口
└─ index.html - 在线示例HTML入口
└─ package.json - 库信息
└─ tsconfig.build.json - 用于构建组件库配套的类型声明文件
└─ vite.config.ts - 构建配置

使用方式

直接先看看组件的使用方式：

src/demo/App.vue

<script setup lang="ts">
import { ref, h, type Ref } from 'vue'
// 组件
import { GridDragResize } from '@/lib/components/GridDragResize'
// 组件配套类型声明
import type { GridDragResizeProps } from '@/lib/components/GridDragResize/types'

// 组件数据结构
const children: Ref<GridDragResizeProps['children']> = ref([
  {
    dragHandler: '.demo-item>button',
    render: () => h('div', { class: "demo-item", style: { background: '#eb9c64' } }, [h('button', 'drag handler')])
  },
  {
    columnStart: 2,
    draggable: false,
    render: () => h('div', { class: "demo-item", style: { background: '#ff8789' } }, 'disable drag')
  },
  {
    rowStart: 2,
    columnStart: 2,
    render: () => h('div', { class: "demo-item", style: { background: '#554e4f' } }, '1')
  },
  {
    rowStart: 2,
    rowEnd: 4,
    columnStart: 4,
    columnEnd: 5,
    render: () => h('div', { class: "demo-item", style: { background: '#8fbf9f' } }, '2')
  },
  {
    rowStart: 4,
    rowEnd: 6,
    columnStart: 2,
    columnEnd: 4,
    render: () => h('div', { class: "demo-item", style: { background: '#346145' } }, '3')
  },
  {
    rowStart: 4,
    rowEnd: 5,
    columnStart: 1,
    columnEnd: 2,
    render: () => h('div', { class: "demo-item", style: { background: '#c2baa6' } }, '4')
  },
])
</script>

<template>
<div class="page">
  <!-- 组件使用 -->
  <GridDragResize :columns="4" :rows="5" :gap="10" :row-size="100" :readonly="false" :children="children">
  </GridDragResize>
  <!-- 组件数据结构 实时状态 -->
  <div v-html="JSON.stringify(children, null, 2).replace(/\n/g, '<br>').replace(/\s/g, '&nbsp; ')"></div>
</div>
</template>

<style lang="less">
// 一些样式初始化

*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  font-weight: normal;
}

body {
  min-height: 100vh;
  color: var(--color-text);
  background: var(--color-background);
  transition:
    color 0.5s,
    background-color 0.5s;
  line-height: 1.6;
  font-family:
    Inter,
    -apple-system,
    BlinkMacSystemFont,
    'Segoe UI',
    Roboto,
    Oxygen,
    Ubuntu,
    Cantarell,
    'Fira Sans',
    'Droid Sans',
    'Helvetica Neue',
    sans-serif;
  font-size: 15px;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}
</style>
<style lang="less">
// 示例样式
.page {
  padding: 32px;
}

.demo-item {
  padding: 10px;
  height: 100%;
}

// 组件样式覆盖
.grid-drag-resize {
  background-color: #eee;

  .grid-drag-resize__item {
    background-color: #ddd;

    &--dragging {
      box-shadow: 0 0 6px 2px #0000ff;
    }
  }
}
</style>

上面可以看出，render 是比较关键的地方，该组件使用方式并非插槽，而是通过数据结构传入的 render 实现每一块的显示的，它可以是 h 可以是一个个其他组件。

接下来，可以看看定义：

组件 Props 定义

// src/lib/components/GridDragResize/types.ts

import type { VNode } from 'vue'

// 子组件的 Props
export interface GridDragResizeItemProps {
  draggable?: boolean
  dragHandler?: string // 满足 querySelector 的查询字符串，指向可拖拉拽的元素位置
  // css display grid 属性
  columnStart?: number
  columnEnd?: number
  rowStart?: number
  rowEnd?: number
  //
  render?: () => VNode
}

// 组件的 Props
export interface GridDragResizeProps {
  dragHandler?: string // 同上，优先级 低于 子组件
  readonly?: boolean // 优先级 低于 子组件 的 draggable
  //
  columns?: number // 列数
  rows?: number // 行数
  gap?: number // 间隙
  columnSize?: number // 列宽，默认是 1fr
  rowSize?: number // 行高，默认是 1fr
  //
  children?: GridDragResizeItemProps[] // 子组件
}

目前为止，定义非常简单。

组件

src/lib/components/GridDragResize/GridDragResize.vue
逻辑说明，请留意代码注释

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

import type { GridDragResizeProps, GridDragResizeItemProps } from './types'

import GridDragResizeItem from './GridDragResizeItem.vue'

const props = withDefaults(defineProps<GridDragResizeProps>(), {
    children: () => []
});

const style = computed(() => {
    return {
        'grid-template-columns': Number.isInteger(props.columns) ? `repeat(${props.columns},${Number.isInteger(props.columnSize) ? `${props.columnSize}px` : '1fr'})` : '',
        'grid-template-rows': Number.isInteger(props.rows) ? `repeat(${props.rows},${Number.isInteger(props.rowSize) ? `${props.rowSize}px` : '1fr'})` : '',
        'grid-gap': Number.isInteger(props.gap) ? `${props.gap}px ${props.gap}px` : ''
    }
})

const rootEle: Ref<HTMLElement | undefined> = ref()

// 给子组件穿透转递组件 Props
provide('parentProps', props)

// 组件位置、大小信息
const rootRect = computed(() => {
    return rootEle?.value?.getBoundingClientRect() ?? {
        height: 0,
        width: 0,
        x: 0,
        y: 0,
        bottom: 0,
        right: 0
    }
})

// 列宽
const columnSize = computed(() => {
    return (rootRect.value.width - (props.gap ?? 0) * ((props.columns ?? 1) - 1)) / (props.columns ?? 1)
})

// 行高
const rowSize = computed(() => {
    return (rootRect.value.height - (props.gap ?? 0) * ((props.rows ?? 1) - 1)) / (props.rows ?? 1)
})

// 根据鼠标拖动偏移量，计算列/行方向上，移动后最新的位置和大小
function calcStartEnd(opts: { size: number, gap: number, span: number, max: number, offset: number, startBefore: number }) {
    let { size, gap, span, max, offset, startBefore } = opts

    let offsetStart = Math.round(offset / (size + gap))

    let start = startBefore + offsetStart

    if (start < 1) {
        start = 1
    }

    if (start + span > max) {
        start = max - span + 1
    }

    return {
        start,
        end: start + span
    }
}

// 当前拖动小组件的数据项
const draggingChild: Ref<GridDragResizeItemProps | undefined> = ref()
// 当前拖动小组件的数据项（初始状态）
const draggingChildBefore: Ref<GridDragResizeItemProps | undefined> = ref()
// 当前拖动小组件的位置、大小信息
const draggingChildRect: Ref<DOMRect | undefined> = ref()

// 拖动开始位置
let dragStartClientX = 0, dragStartClientY = 0;

// 拖动偏移量
let dragOffsetClientX = 0, dragOffsetClientY = 0;

let dragging = false

// 开始拖动
function dragstart(e: MouseEvent) {
    if (!props.readonly) {
        dragging = true

        // 记录 拖动开始位置
        dragStartClientX = e.clientX
        dragStartClientY = e.clientY
    }
}

// 拖动中
function drag(e: MouseEvent) {
    if (dragging && draggingChild.value && draggingChildRect.value) {
        // 计算 拖动开始位置
        dragOffsetClientX = e.clientX - dragStartClientX
        dragOffsetClientY = e.clientY - dragStartClientY

        // 当前拖动小组件的 grid 大小
        let rowSpan = (draggingChild.value.rowEnd ?? draggingChild.value.rowStart ?? 1) - (draggingChild.value.rowStart ?? 1)
        let columnSpan = (draggingChild.value.columnEnd ?? draggingChild.value.columnStart ?? 1) - (draggingChild.value.columnStart ?? 1)

        // 边界处理
        if (rowSpan <= 0) {
            rowSpan = 1
        }

        if (columnSpan <= 0) {
            columnSpan = 1
        }
        
        
        // 计算行方向上，移动后最新的位置和大小
        let { start: rowStart, end: rowEnd } = calcStartEnd({
            size: rowSize.value, gap: (props.gap ?? 0), span: rowSpan, max: props.rows ?? 1, offset: dragOffsetClientY, startBefore: draggingChildBefore.value?.rowStart ?? 1
        })

        // 计算列方向上，移动后最新的位置和大小
        let { start: columnStart, end: columnEnd } = calcStartEnd({
            size: columnSize.value, gap: (props.gap ?? 0), span: columnSpan, max: props.columns ?? 1, offset: dragOffsetClientX, startBefore: draggingChildBefore.value?.columnStart ?? 1
        })

        // 当前拖动小组件的数据项
        draggingChild.value.columnStart = columnStart
        draggingChild.value.columnEnd = columnEnd
        draggingChild.value.rowStart = rowStart
        draggingChild.value.rowEnd = rowEnd
    }
}

// 拖动结束
function dragend(e: MouseEvent) {
    e.stopPropagation()

    dragging = false

    draggingChild.value = undefined
}

// 超出组件区域，补充结束事件
document.body.addEventListener('mouseup', dragend)
</script>

<template>
<div class="grid-drag-resize" :style="style" @mousedown="dragstart" @mousemove="drag" @mouseup="dragend" ref="rootEle">
    <template v-for="(child, idx) of props.children" :key="idx">
        <GridDragResizeItem v-bind="child" v-model:column-start="child.columnStart" v-model:column-end="child.columnEnd"
            v-model:row-start="child.rowStart" v-model:row-end="child.rowEnd"
            @dragging="(rect) => { draggingChild = child; draggingChildBefore = { ...child }; draggingChildRect = rect }"
            :style="{ 'zIndex': draggingChild === child ? props.children.length + 1 : idx + 1 }"
            :class="{ 'grid-drag-resize__item--dragging': draggingChild === child }">
            <component :is="child.render"></component>
        </GridDragResizeItem>
    </template>
</div>
</template>

子组件

src/lib/components/GridDragResize/GridDragResizeItem.vue
逻辑说明，请留意代码注释

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

import type { GridDragResizeProps, GridDragResizeItemProps } from './types'

const parentProps = inject<GridDragResizeProps>('parentProps')

const props = withDefaults(defineProps<GridDragResizeItemProps>(), {
    draggable: true
});

const emit = defineEmits(['update:columnStart', 'update:columnEnd', 'update:rowStart', 'update:rowEnd', 'dragging'])

// 数据整理
watchEffect(() => {
    if (props.columnStart !== void 0) {
        if (props.columnEnd === void 0 || props.columnEnd < props.columnStart) {
            emit('update:columnEnd', props.columnStart + 1)
        }
    } else {
        emit('update:columnStart', 1)
    }

    if (props.rowStart !== void 0) {
        if (props.rowEnd === void 0 || props.rowEnd < props.rowStart) {
            emit('update:rowEnd', props.rowStart + 1)
        }
    } else {
        emit('update:rowStart', 1)
    }
})

// 样式
const style = computed(() => {
    return {
        'grid-column-start': props.columnStart,
        'grid-column-end': props.columnEnd,
        'grid-row-start': props.rowStart,
        'grid-row-end': props.rowEnd,
    }
})

const itemEle: Ref<HTMLElement | undefined> = ref()

const dragHandlerParsed = computed(() => props.dragHandler ?? parentProps?.dragHandler)
const draggableParsed = computed(() => parentProps?.readonly ? false : props.draggable)

// dragHandler 定位、处理、事件绑定
watchEffect(() => {
    if (draggableParsed.value && dragHandlerParsed.value && itemEle.value) {
        const handlerEle = itemEle.value.querySelector(dragHandlerParsed.value)
        if (handlerEle instanceof HTMLElement) {
            handlerEle.style.cursor = 'grab'

            handlerEle.addEventListener('mousedown', dragstart)
        }
    }
})

// 拖动开始
function dragstart() {
    if (draggableParsed.value) {
        // 通知父组件 当前拖动小组件
        emit('dragging', itemEle?.value?.getBoundingClientRect() ?? {
            height: 0,
            width: 0,
            x: 0,
            y: 0,
            bottom: 0,
            right: 0
        })
    }
}
</script>

<template>
<div class="grid-drag-resize__item" :class="{
    'grid-drag-resize__item--draggable': draggableParsed,
    'grid-drag-resize__item--draggable-full': draggableParsed && dragHandlerParsed === void 0
}" :style="style" @mousedown="() => dragHandlerParsed ? undefined : dragstart()" ref="itemEle">
    <slot></slot>
</div>
</template>

样式

.grid-drag-resize {
  display: grid;

  .grid-drag-resize__item {
    &--draggable-full {
      cursor: grab;
      user-select: none;
    }

    &--dragging {
      opacity: 0.6;
    }
  }
}

组件入口

// src/lib/components/GridDragResize/index.ts
import GridDragResize from './GridDragResize.vue'
import GridDragResizeItem from './GridDragResizeItem.vue'

import './style.less'

export * from './types'

export { GridDragResize, GridDragResizeItem }