23 KiB
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.
:::code-group
<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>
<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.
::: code-group
<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>
<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>
:::
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.
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
targetHandle: Position.Top, // or Bottom, Left, Right,
sourceHandle: 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.
import { ref } from 'vue'
import { Position } from '@vue-flow/core'
const nodes = ref([
{
id: '1',
label: 'Input Node',
type: 'input',
sourceHandle: 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.
import { ref } from 'vue'
import { Position } from '@vue-flow/core'
const nodes = ref([
{
id: '1',
label: 'Output Node',
type: 'output',
targetHandle: 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.
::: code-group
import { ref } from '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 setup>
import { Position } from '@vue-flow/core'
const props = defineProps(['label'])
</script>
<template>
<div>
<Handle type="target" :position="Position.Top" />
<div>{{ label }}</div>
<Handle type="source" :position="Position.Bottom" />
</div>
</template>
import { ref } from 'vue'
import type { Node } from '@vue-flow/core'
// 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: '1',
label: 'Node 1',
// this will create the node-type `special`
type: 'special',
position: { x: 150, y: 50 },
},
// 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
{
id: '1',
label: 'Node 1',
type: 'invalid',
position: { x: 150, y: 50 },
}
])
<script setup lang="ts">
import type { NodeProps } from '@vue-flow/core'
import { Position } from '@vue-flow/core'
import { CustomData, CustomEvents } from './nodes'
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.
<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. :::
<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>
::: tip You can find a working example here. :::
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:
| Name | Definition | Type | Optional |
|---|---|---|---|
| id | Node id | string | |
| type | Node type | string | |
| selected | Is node selected | boolean | |
| dragging | Is node dragging | boolean | |
| connectable | Is node connectable | boolean | |
| position | Relative position of a node | XYPosition | |
| zIndex | Node z-index | number | |
| dimensions | Node size | Dimensions | |
| data | Custom data object | Any object | |
| events | Node events and custom events | NodeEventsOn | |
| label | Node label | string, Component | |
| isValidTargetPos | Called when target handle is used for connection | ValidConnectionFunc | |
| isValidSourcePos | Called when source handle is used for connection | ValidConnectionFunc | |
| parentNode | Parent node id | string | |
| targetPosition | Target handle position | Position | |
| sourcePosition | Source handle position | Position | |
| dragHandle | Node drag handle class | string |
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 using binding listeners to the <VueFlow> component.
::: code-group
<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>
<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.
.vue-flow__node-custom {
background: #9CA8B3;
color: #fff;
padding: 10px;
}
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:
::: code-group
<!-- 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',
}
}
</script>
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',
}
<script setup>
import { ref } from 'vue'
const elements = ref([
{
id: '1',
label: 'Node 1',
position: { x: 50, y: 50 },
data: {
hello: 'world',
}
},
])
function onSomeEvent() {
elements.value[0].data = {
...elements.value[0].data,
hello: 'world',
}
}
</script>
<template>
<VueFlow v-model="elements" />
</template>
:::
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.
<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.
<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
updateNodeInternalsevent from your customized node component: This doesn't require any parameters to be passed.
::: code-group
import { useVueFlow } from '@vue-flow/core'
const { updateNodeInternals } = useVueFlow()
const onSomeEvent = () => {
updateNodeInternals(['1'])
}
<script setup>
const emits = defineEmits(['updateNodeInternals'])
const onSomeEvent = () => {
emits('updateNodeInternals')
}
</script>
:::