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Introduction to Nodes

Nodes are the underlying components of your graph. They can be any kind of data you want to visualize in your graph, existing independently and being interconnected through edges to create a data map.

Remember, every node is unique and thus requires a unique id and an XY-position.

For the full list of options available for a node, check out the Node Interface.

Adding Nodes to the Graph

Nodes are generally created by adding them to the mode-value (using v-model) or to the nodes prop of the Vue Flow component. This can be done dynamically at any point in your component's lifecycle.

vue

<script setup>
import { ref, onMounted } from 'vue'
import { VueFlow } from '@vue-flow/core'

const elements = ref([
  {
    id: '1',
    position: { x: 50, y: 50 },
    label: 'Node 1',
  }
]);

onMounted(() => {
  elements.value.push({
    id: '2',
    label: 'Node 2',
    position: { x: 150, y: 50 },
  })
})
</script>

<template>
  <VueFlow v-model="elements"/>
</template>
vue

<script setup lang="ts">
import { ref, onMounted } from 'vue'
import type { Elements } from '@vue-flow/core'
import { VueFlow } from '@vue-flow/core'

const elements = ref<Elements>([
   {
     id: '1',
     position: { x: 50, y: 50 },
     label: 'Node 1',
   }
]);

onMounted(() => {
   elements.value.push({
     id: '2',
     label: 'Node 2',
     position: { x: 150, y: 50 },
   })
})
</script>

<template>
  <VueFlow v-model="elements"/>
</template>

If you are working with more complex graphs that necessitate extensive state access, the useVueFlow composable should be employed. The addNodes action is available through useVueFlow, allowing you to add nodes straight to the state.

What's more, this action isn't limited to the component rendering the graph; it can be utilized elsewhere, like in a Sidebar or Toolbar.

vue

<script setup>
import { ref } from 'vue'
import { VueFlow, useVueFlow } from '@vue-flow/core'

const initialNodes = ref([
  {
    id: '1',
    position: { x: 50, y: 50 },
    label: 'Node 1',
  }
])
const { addNodes } = useVueFlow()

function generateRandomNode() {
  return {
    id: Math.random().toString(),
    position: { x: Math.random() * 500, y: Math.random() * 500 },
    label: 'Random Node',
  }
}

function onAddNode() {
  // add a single node to the graph
  addNodes(generateRandomNode())
}

function onAddNodes() {
  // add multiple nodes to the graph
  addNodes(Array.from({ length: 10 }, generateRandomNode))
}
</script>

<template>
  <VueFlow :nodes="initialNodes" />
  
  <button type="button" @click="onAddNode">Add a node</button>
  <button type="button" @click="onAddNodes">Add multiple nodes</button>
</template>
vue
<script setup lang="ts">
import { ref } from 'vue'  
import type { Node } from '@vue-flow/core'  
import { VueFlow, useVueFlow } from '@vue-flow/core'

const initialNodes = ref<Node[]>([
  {
    id: '1',
    position: { x: 50, y: 50 },
    label: 'Node 1',
    data: {},
  }
])
const { addNodes } = useVueFlow()

function generateRandomNode() {
  return {
    id: Math.random().toString(),
    position: { x: Math.random() * 500, y: Math.random() * 500 },
    label: 'Random Node',
    data: { 
      hello: 'world',
    }
  }
}

function onAddNode() {
  // add a single node to the graph
  addNodes(generateRandomNode())
}

function onAddNodes() {
  // add multiple nodes to the graph
  addNodes(Array.from({ length: 10 }, generateRandomNode))
}
</script>

<template>
  <VueFlow :nodes="initialNodes" />
  
  <button type="button" @click="onAddNode()">Add a node</button>
  <button type="button" @click="onAddNodes()">Add multiple nodes</button>
</template>

Removing Nodes from the Graph

Similar to adding nodes, nodes can be removed from the graph by removing them from the mode-value (using v-model) or from the nodes prop of the Vue Flow component.

vue

<script setup>
import { ref } from 'vue'

const elements = ref([
  {
    id: '1',
    position: { x: 50, y: 50 },
    label: 'Node 1',
  },
  {
    id: '2',
    position: { x: 150, y: 50 },
    label: 'Node 2',
  }
])

function onRemoveNode() {
  elements.value.pop()
}
</script>

<template>
  <VueFlow v-model="elements" />
  
  <button type="button" @click="onRemoveNode">Remove a node</button>
</template>

When working with complex graphs with extensive state access, you should use the useVueFlow composable. The removeNodes action is available through useVueFlow, allowing you to remove nodes straight from the state.

What's more, this action isn't limited to the component rendering the graph; it can be utilized elsewhere, like in a Sidebar, Toolbar or the Edge itself.

vue

<script setup>
import { ref } from 'vue'
import { VueFlow, useVueFlow } from '@vue-flow/core'

const initialNodes = ref([
  {
    id: '1',
    position: { x: 50, y: 50 },
    label: 'Node 1',
  },
  {
    id: '2',
    position: { x: 150, y: 50 },
    label: 'Node 2',
  }
])

const { removeNodes } = useVueFlow()

// remove a single node from the graph
function onRemoveNode() {
  removeNodes('1')
}

// remove multiple nodes from the graph
function onRemoveNodes() {
  removeNodes(['1', '2'])
}
</script>

<template>
  <VueFlow :nodes="initialNodes" />
  
  <button type="button" @click="onRemoveNode">Remove a node</button>
  <button type="button" @click="onRemoveNodes">Remove multiple nodes</button>
</template>

Updating Node Data

Since nodes are reactive object, you can update their data at any point by simply mutating it. This allows you to disable or enable handles, change the label, or even add new properties to the data object at any point in time.

There are multiple ways of achieving this, here are some examples:

vue
<!-- CustomNode.vue -->
<script setup>
import { useNode } from '@vue-flow/core'

// `useNode` returns us the node object straight from the state
// since the node obj is reactive, we can mutate it to update our nodes' data
const { node } = useNode()

function onSomeEvent() {
  node.data = {
    ...node.data,  
    hello: 'world',
  }
  
  // you can also mutate properties like `selectable` or `draggable`
  node.selectable = false
  node.draggable = false
}
</script>
ts
import  { useVueFlow } from '@vue-flow/core'

const instance = useVueFlow()

// find the node in the state by its id
const node = instance.findNode(nodeId)

node.data = {
  ...node.data,
  hello: 'world',
}

// you can also mutate properties like `selectable` or `draggable`
node.selectable = false
node.draggable = false
vue
<script setup>
import { ref } from 'vue'

const elements = ref([
  {
    id: '1',
    label: 'Node 1',
    position: { x: 50, y: 50 },
    data: {
      hello: 'world',
    }
  },
])

function onSomeEvent(nodeId) {
  const node = elements.value.find((node) => node.id === nodeId)

  node.data = {
    ...elements.value[0].data,
    hello: 'world',
  }
    
  // you can also mutate properties like `selectable` or `draggable`
  node.selectable = false
  node.draggable = false
}
</script>

<template>
  <VueFlow v-model="elements" />
</template>

Predefined Node-Types

Vue Flow provides several built-in node types that you can leverage immediately. The included node types are default, input, and output.

Default Node

A default node includes two handles and serves as a branching junction in your map.

You have the freedom to determine the location of handles in the node's definition.

ts
import { ref } from 'vue'
import { Position } from '@vue-flow/core'

const nodes = ref([
  {
    id: '1',
    label: 'Default Node',
    type: 'default', // You can omit this as it's the fallback type
    targetPosition: Position.Top, // or Bottom, Left, Right,
    sourcePosition: Position.Bottom, // or Top, Left, Right,
  }
])

Input Node

An input node features a single handle, which is by default positioned at the bottom. It represents a starting point of your map.

ts
import { ref } from 'vue'
import { Position } from '@vue-flow/core'

const nodes = ref([
  {
    id: '1',
    label: 'Input Node',
    type: 'input',
    sourcePosition: Position.Bottom, // or Top, Left, Right,
  }
])

Output Node

An output node also possesses a single handle, although it is typically found at the top. This node represents a conclusion point of your map.

ts
import { ref } from 'vue'
import { Position } from '@vue-flow/core'

const nodes = ref([
  {
    id: '1',
    label: 'Output Node',
    type: 'output',
    targetPosition: Position.Top, // or Bottom, Left, Right,
  }
])

User-Defined Nodes

On top of the default node types mentioned earlier, you can create as many custom node-types as you need. Node-types are determined from your nodes' definitions.

vue
<script setup>
import { ref } from 'vue'
import { VueFlow } from '@vue-flow/core'

import CustomNode from './CustomNode.vue'
import SpecialNode from './SpecialNode.vue'

export const nodes = ref([
  {
    id: '1',
    label: 'Node 1',
    // this will create the node-type `custom`
    type: 'custom',
    position: { x: 50, y: 50 },
  },
  {
    id: '1',
    label: 'Node 1',
    // this will create the node-type `special`
    type: 'special',
    position: { x: 150, y: 50 },
  }
])
</script>

<template>
  <VueFlow :nodes="nodes">
    <template #node-custom="customNodeProps">
      <CustomNode v-bind="customNodeProps" />
    </template>
    
    <template #node-special="specialNodeProps">
      <SpecialNode v-bind="specialNodeProps" />
    </template>
  </VueFlow>
</template>
vue
<script setup>
import { Position } from '@vue-flow/core'

// props were passed from the slot using `v-bind="customNodeProps"`
const props = defineProps(['label'])
</script>

<template>
  <div>
    <Handle type="target" :position="Position.Top" />
    <div>{{ label }}</div>
    <Handle type="source" :position="Position.Bottom" />
  </div>
</template>
vue
<script setup lang="ts">
import { ref } from 'vue'
import type { Node } from '@vue-flow/core'
import { VueFlow } from '@vue-flow/core'

import CustomNode from './CustomNode.vue'
import SpecialNode from './SpecialNode.vue'

// You can pass 3 optional generic arguments to the Node interface, allowing you to define:
// 1. The data object type
// 2. The events object type
// 3. The possible node types

export interface CustomData {
  hello: string
}

export interface CustomEvents {
  onCustomEvent: (event: MouseEvent) => void
}

type CustomNodeTypes = 'custom' | 'special'

type CustomNode = Node<CustomData, CustomEvents, CustomNodeTypes>

export const nodes = ref<CustomNode[]>([
  {
    id: '1',
    label: 'Node 1',
    // this will create the node-type `custom`
    type: 'custom',
    position: { x: 50, y: 50 },
  },
  {
    id: '2',
    label: 'Node 2',
    // this will create the node-type `special`
    type: 'special',
    position: { x: 150, y: 50 },
  },
    
  {
    id: '3', 
    label: 'Node 3',
    // this will throw a type error, as the type is not defined in the CustomEdgeTypes
    // regardless it would be rendered as a default edge type
    type: 'invalid',
    position: { x: 150, y: 50 },
  }
])
</script>

<template>
  <VueFlow :nodes="nodes">
    <template #node-custom="customNodeProps">
      <CustomNode v-bind="customNodeProps" />
    </template>
    
    <template #node-special="specialNodeProps">
      <SpecialNode v-bind="specialNodeProps" />
    </template>
  </VueFlow>
</template>
vue
<script setup lang="ts">
import type { NodeProps } from '@vue-flow/core'  
import { Position } from '@vue-flow/core'

import { CustomData, CustomEvents } from './nodes'

// props were passed from the slot using `v-bind="customNodeProps"`
const props = defineProps<NodeProps<CustomData, CustomEvents>>()
  
console.log(props.data.hello) // 'world'
</script>

<template>
  <div>
    <Handle type="target" :position="Position.Top" />
    <div>{{ label }}</div>
    <Handle type="source" :position="Position.Bottom" />
  </div>
</template>

Vue Flow will then attempt to resolve this node-type to a component. Priority is given to a definition in the nodeTypes object of the state. Next, it tries to match the component to a globally registered one with the same name. Finally, it searches for a provided template slot to fill in the node-type.

If no methods produce a result in resolving the component, the default node-type is used as a fallback.

Template slots

One of the easiest ways to define custom nodes is, by passing them as template slots. Dynamic resolution to slot-names is done for your user-defined node-types, meaning a node with the type custom is expected to have a slot named #node-custom.

vue
<script setup>
import { VueFlow } from '@vue-flow/core'
import CustomNode from './CustomNode.vue'

const elements = ref([
  {
    id: '1',
    label: 'Node 1',
    type: 'custom',
    position: { x: 50, y: 50 },
  }
])
</script>

<template>
  <VueFlow v-model="elements">
    <!-- the expected slot name is `node-custom` -->
    <template #node-custom="props">
      <CustomNode v-bind="props" />
    </template>
  </VueFlow>
</template>

Node-types object

Alternatively, node-types can also be defined by passing an object as a prop to the VueFlow component (or as an option to the composable).

WARNING

Take precaution to mark your components as raw (utilizing the marked function from the Vue library) to prevent their conversion into reactive objects. Otherwise, Vue will display a warning on the console.

vue
<script setup>
import { markRaw } from 'vue'
import CustomNode from './CustomNode.vue'
import SpecialNode from './SpecialNode.vue'

const nodeTypes = {
  custom: markRaw(CustomNode),
  special: markRaw(SpecialNode),
}

const elements = ref([
  {
    id: '1',
    label: 'Node 1',
    type: 'custom',
  },
  {
    id: '1',
    label: 'Node 1',
    type: 'special',
  }
])
</script>

<template>
  <VueFlow v-model="elements" :node-types="nodeTypes" />
</template>

Node Props

Your custom nodes are enclosed so that fundamental functions like dragging or selecting operate. But you may wish to expand on these features or implement your business logic inside nodes, thus your nodes receive the following properties:

Prop NameDescriptionTypeOptional
idUnique node idstring
typeNode Typestring
selectedIs node selectedboolean
connectableCan node handles be connectedHandleConnectable
positionNode's x, y (relative) position on the graphXYPosition
dimensionsDom element dimensions (width, height)Dimensions
labelNode label, either a string or a VNode. h('div', props, children)string | VNode | Component | Object
isValidTargetPos deprecatedCalled when used as target for new connectionValidConnectionFunc
isValidSourcePos deprecatedCalled when used as the source for a new connectionValidConnectionFunc
parentParent node idstring
draggingIs node currently draggingboolean
resizingIs node currently resizingboolean
zIndexNode z-indexnumber
targetPositionHandle positionPosition
sourcePositionHandle positionPosition
dragHandleDrag handle query selectorstring
dataAdditional data of nodeany object
eventsContextual and custom events of nodeNodeEventsOn

Node Events

Vue Flow provides two main ways of listening to node events, either by using useVueFlow to bind listeners to the event handlers or by binding them to the <VueFlow> component.

vue
<script setup>
import { ref } from 'vue'  
import { VueFlow, useVueFlow } from '@vue-flow/core'

// useVueFlow provides access to the event handlers
const { 
  onNodeDragStart, 
  onNodeDrag,
  onNodeDragStop, 
  onNodeClick, 
  onNodeDoubleClick, 
  onNodeContextMenu, 
  onNodeMouseEnter, 
  onNodeMouseLeave, 
  onNodeMouseMove 
} = useVueFlow()
  
const elements = ref([
  {
    id: '1',
    label: 'Node 1',
    position: { x: 50, y: 50 },
  },
])
  
// bind listeners to the event handlers
onNodeDragStart((event) => {
  console.log('Node drag started', event)
})

onNodeDrag((event) => {
  console.log('Node dragged', event)
})

onNodeDragStop((event) => {
  console.log('Node drag stopped', event)
})
  
// ... and so on  
</script>

<template>
  <VueFlow v-model="elements" />
</template>
vue
<script setup>
import { ref } from 'vue'
import { VueFlow } from '@vue-flow/core'

const elements = ref([
  {
    id: '1',
    label: 'Node 1',
    position: { x: 50, y: 50 },
  },
])
</script>

<template>
  <!-- bind listeners to the event handlers -->
  <VueFlow
    v-model="elements"
    @node-drag-start="console.log('drag start', $event)"
    @node-drag="console.log('drag', $event)"
    @node-drag-stop="console.log('drag stop', $event)"
    @node-click="console.log('click', $event)"
    @node-double-click="console.log('dblclick', $event)"
    @node-contextmenu="console.log('contextmenu', $event)"
    @node-mouse-enter="console.log('mouseenter', $event)"
    @node-mouse-leave="console.log('mouseleave', $event)"
    @node-mouse-move="console.log('mousemove', $event)"
  />
</template>

Interact to see events in browser console

Customizing Appearance

TIP

To override the styles of the default theme, visit the Theming section.

User-Defined Nodes

When constructing a new node type, it's necessary for you to add some styling specific to it. User-created nodes don't have any default styles associated and thus need custom styling.

css
.vue-flow__node-custom {
    background: #9CA8B3;
    color: #fff;
    padding: 10px;
}

Implementing Scrolling within Nodes

Sometimes, a node might contain a large amount of content, making it difficult for users to view everything without the aid of a scroll function. To facilitate this scrolling ability without invoking zoom or pan behaviors on the node, Vue Flow provides the noWheelClassName property.

The noWheelClassName property allows you to specify a class name that, when applied to a node, will disable the default zoom-on-scroll or pan-on-scroll events on that particular node.

By default, the noWheelClassName is nowheel.

vue
<script setup>
import { ref } from 'vue'

const listItems = ref(Array.from({ length: 100 }, (_, i) => i))  
</script>

<template>
  <div class="custom-node-container">
    <ul class="nowheel">
      <li v-for="item in listItems" :key="item">Item {{ item }}</li>
    </ul>
  </div>
</template>

Preventing Drag Behavior withing Nodes

There are certain scenarios where you might need to interact with the contents of a node without triggering a drag action on the node itself. This can be particularly useful when nodes contain interactive elements like input boxes, buttons, or sliders that you want your users to engage with.

To accomplish this, Vue Flow provides a noDragClassName property. This property allows specification of a class name, which when applied to an element within a node, prevents triggering a drag action on the node when the user interacts with that element.

By default, the noDragClassName is set as nodrag.

vue
<script setup>
import { ref } from 'vue'

const inputValue = ref('')
</script>

<template>
  <div class="custom-node-container">
    <input class="nodrag" v-model="inputValue" />
  </div>
</template>

Working with Dynamic Handle Positions / Adding Handles Dynamically

TIP

In Vue Flow 1.x, there's no need to manually invoke updateNodeInternals when dynamically adding handles. Upon mounting, handles will automatically attempt to attach to the node. However, if for any reason this isn't happening as expected, you can stick to the guideline provided below to enforce Vue Flow to update the node internals.

At times, you may need to modify handle positions dynamically or programmatically add new handles to a node. In this scenario, the updateNodeInternals method found in Vue Flow's API comes in handy.

Invoking this method is vital when dealing with dynamic handles. If not, the node might fail to recognize these new handles, resulting in misaligned edges.

The updateNodeInternals function can be deployed in one of two ways:

  • Using the store action: This approach allows you to update several nodes at once by passing their IDs into the method.
  • Emitting the updateNodeInternals event from your customized node component: This doesn't require any parameters to be passed.
js
import { useVueFlow } from '@vue-flow/core'

const { updateNodeInternals } = useVueFlow()

const onSomeEvent = () => {
  updateNodeInternals(['1'])
}
vue
<script setup>
const emits = defineEmits(['updateNodeInternals'])

const onSomeEvent = () => {
  emits('updateNodeInternals')
}
</script>

Released under the MIT License.