Nodes ​

Nodes are the building blocks of your graph. They represent any sort of data you want to present in your graph.

They can exist on their own but can be connected to each other with edges to create a map.

Each node requires a unique id and an xy-position.

You can view the full options-list for a node here.

Usage ​

Generally you create nodes by adding them to the model-value or the nodes prop of the Vue Flow component.

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

export default defineComponent({
  components: { VueFlow },
  data() {
    return {
      elements: [
        {
          id: '1',
          position: { x: 50, y: 50 },
          label: 'Node 1',
        }
      ]
    }
  },
  mounted() {
    // Add an element after mount
    this.elements.push(
      {
        id: '2',
        position: { x: 150, y: 50 },
        label: 'Node 2',
      }
    )
  }
})
</script>

<template>
  <div style="height: 300px">
    <VueFlow v-model="elements" />
  </div>
</template>

For more advanced graphs that require more state access you will want to use the useVueFlow composable. useVueFlow will provide the addNodes action, which you can use to add nodes directly to the state.

This action can be even be used outside the component that is rendering the graph, like a Sidebar or a Toolbar.

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

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

onMounted(() => {
  // Add an element after mount
  addNodes([
    {
      id: '2',
      position: { x: 150, y: 50 },
      label: 'Node 2',
    }
  ])
})
</script>

<template>
  <div style="height: 300px">
    <VueFlow />
  </div>
</template>

Default Node-Types ​

Vue Flow comes with built-in nodes that you can use right out of the box. These node types include default, input and output.

Default Node ​

A default node comes with two handles. It represents a branching point in your map.

You can specify the position of handles in the node definition.

const nodes = [
  {
    id: '1',
    label: 'Node 1',
    targetHandle: Position.Top, // or Bottom, Left, Right,
    sourceHandle: Position.Right,
  }
]

Input Node ​

An input node has a single handle, located at the bottom by default. It represents a starting point of your map.

Output Node ​

An output node has a single handle, located at the top by default. It represents an ending point of your map.

Custom Nodes ​

In addition to the default node types from the previous chapter, you can define any amount of custom node-types. Node-types are inferred from your node's definition.

const nodes = [
  {
    id: '1',
    label: 'Node 1',
    type: 'custom',
    position: { x: 50, y: 50 },
  },
  {
    id: '1',
    label: 'Node 1',
    type: 'special',
    position: { x: 150, y: 50 },
  }
]

Vue Flow will now try to resolve this node-type to a component. First and foremost we will look for a definition in the nodeTypes object of the state. After that we will try to resolve the component to a globally registered one that matches the exact name. Finally, we will check if a template slot has been provided to fill the node-type.

If none of these methods succeed in resolving the component the default node-type will be used as a fallback.

Template slots ​

The easiest way to define custom nodes is, by passing them as template slots. Your custom node-types are dynamically resolved to slot-names, meaning a node with the type custom will expect a slot to have the name node-custom.

<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">
    <template #node-custom="props">
      <CustomNode v-bind="props" />
    </template>
  </VueFlow>
</template>

Node-types object ​

You can also define node-types by passing an object as a prop to the VueFlow component (or as an option to the composable).

<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>
  <div style="height: 300px">
    <VueFlow v-model="elements" :node-types="nodeTypes" />
  </div>
</template>

Node Template ​

You can also set a template per node, which will overwrite the node-type component but will retain the type otherwise.

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

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

const elements = ref([
  {
    id: '1',
    label: 'Node 1',
    type: 'custom',
    template: markRaw(OverwriteCustomNode),
  },
  {
    id: '1',
    label: 'Node 1',
    type: 'special',
  }
])
</script>
<template>
  <div style="height: 300px">
    <VueFlow v-model="elements" :node-types="nodeTypes" />
  </div>
</template>

(Custom) Node Props ​

Your custom nodes are wrapped so that the basic functions like dragging or selecting work. But you might want to extend on that functionality or implement your own business logic inside of nodes, therefore your nodes receive the following props:

(Custom) Node Events ​

In addition to the event handlers that you can access through useVueFlow or the Vue Flow component, you can also pass in event handlers in your initial node definition, or you can access the node events through the events prop passed to your node components.

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

const elements = ref([
  {
    id: '1',
    label: 'Node 1',
    type: 'custom',
    position: { x: 50, y: 50 },
    events: {
      click: () => {
        console.log('Node 1 clicked')
      },
      customEvent: () => {
        console.log('Node 1 custom event')
      },
    }
  }
])
</script>

As you can see above, you can also pass in custom event handlers. These will not be called by Vue Flow but can be used to forward callback functions to your custom components. The click handler is part of the NodeEventsHandler interface, meaning it will be triggered when the node is clicked.

<script lang="ts" setup>
import type { NodeProps, NodeEventsOn } from '@vue-flow/core'

// define your events
interface CustomNodeEvents {
  click: NodeEventsOn['click']
  customEvent: (input: string) => void
}

interface CustomNodeProps extends NodeProps<any, CustomNodeEvents> {
  id: string
  events: CustomNodeEvents
}

const props = defineProps<CustomNodeProps>()

props.events.click(() => {
  console.log(`Node ${props.id} clicked`)
})

// custom events are just functions, they are not hooks which you can listen to like `click`
props.events.customEvent('custom event triggered')
</script>

<template>
  <!-- Omitted for simplicty -->
</template>

Styling ​

Custom Nodes ​

When you create a new node type you also need to implement some styling. Your custom node has no default styles.

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

Scrolling inside a node ​

You can use the noWheelClassName prop to define a class name which will prevent zoom-on-scroll or pan-on-scroll behavior on that node. By default, the noWheelClassName is nowheel. By adding this class you can enable scrolling inside a node without triggering zoom-pan behavior.

Dragging inside a node ​

You can use the noDragClassName prop to define a class name which will not trigger dragging behavior on that node. By default, the noDragClassName is nodrag.

Dynamic handle positions / Adding handles dynamically ​

When working with dynamic handle positions or adding handles dynamically, you need to use the updateNodeInternals method.

You need to call this method otherwise your node will not respond to the new handles and edges will be misaligned.

You can either use the store action to update multiple nodes at once by passing their ids into the method, or you can emit the updateNodeInternals event from your custom node component without passing any parameters.

Examples ​

• Using store action

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

const { updateNodeInternals } = useVueFlow()

const onSomeEvent = () => {
  updateNodeInternals(['1'])
}
</script>

• Emitting event from custom component

<script setup>
const emits = defineEmits(['updateNodeInternals'])

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