Lodin/ react-vtree

(2.0.4) 3 months ago

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React

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Lodin

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Description

React component for efficiently rendering large tree structures

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Vlad Rindevich Lodin

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Readme

react-vtree

Name: react-vtree
Brand: react-vtree
SKU: //Lodin/react-vtree
Rating: 2.1875 (175 reviews)

This package provides a lightweight and flexible solution for rendering large tree structures. It is built on top of the react-window library.

Attention! This library is entirely rewritten to work with the

react-window

. If you are looking for the tree view solution for the react-virtualized, take a look at react-virtualized-tree.

NOTE: This is the documentation for version

3.x.x

. For version

2.x.x

see this branch.

Installation

# npm npm i react-window react-vtree

Yarn

yarn add react-window react-vtree

Usage

FixedSizeTree

Example

You can also take a look at the very similar example at the Storybook:

import {FixedSizeTree as Tree} from 'react-vtree';

// Tree component can work with any possible tree structure because it uses an
// iterator function that the user provides. Structure, approach, and iterator
// function below is just one of many possible variants.
const treeNodes = [
  {
    name: 'Root #1',
    id: 'root-1',
    children: [
      {
        children: [
          {id: 'child-2', name: 'Child #2'},
          {id: 'child-3', name: 'Child #3'},
        ],
        id: 'child-1',
        name: 'Child #1',
      },
      {
        children: [{id: 'child-5', name: 'Child #5'}],
        id: 'child-4',
        name: 'Child #4',
      },
    ],
  },
  {
    name: 'Root #2',
    id: 'root-2',
  },
];
// This helper function constructs the object that will be sent back at the step
// [2] during the treeWalker function work. Except for the mandatory data
// field you can put any additional data here.
const getNodeData = (node, nestingLevel) => ({
  data: {
    id: node.id.toString(), // mandatory
    isLeaf: node.children.length === 0,
    isOpenByDefault: true, // mandatory
    name: node.name,
    nestingLevel,
  },
  nestingLevel,
  node,
});
// The treeWalker function runs only on tree re-build which is performed
// whenever the treeWalker prop is changed.
function* treeWalker() {
  // Step [1]: Define the root node of our tree. There can be one or
  // multiple nodes.
  for (let i = 0; i < treeNodes.length; i++) {
    yield getNodeData(treeNodes[i], 0);
  }
  while (true) {
    // Step [2]: Get the parent component back. It will be the object
    // the getNodeData function constructed, so you can read any data from it.
    const parent = yield;
for (let i = 0; i &lt; parent.node.children.length; i++) {
  // Step [3]: Yielding all the children of the provided component. Then we
  // will return for the step [2] with the first children.
  yield getNodeData(parent.node.children[i], parent.nestingLevel + 1);
}
  }
}
// Node component receives all the data we created in the treeWalker +
// internal openness state (isOpen), function to change internal openness
// state (setOpen) and style parameter that should be added to the root div.
const Node = ({data: {isLeaf, name}, isOpen, style, setOpen}) => (
  

    {!isLeaf && (
       setOpen(!isOpen)}>
        {isOpen ? '-' : '+'}
      
    )}
    {name}
  
);
ReactDOM.render(
  
    {Node}
  ,
  document.querySelector('#root'),
);

Props

Props inherited from

FixedSizeList

You can read more about these properties in the

FixedSizeList

documentation.

~~children: component~~
. Uses own implementation, see below.
```
className: string = ""
```
```
direction: strig = "ltr"
```
```
height: strig | number
```
```
initialScrollOffset: number = 0
```
```
innerRef: function | createRef object
```
. This property works as it described in the
```
react-window
```
. For getting a
```
FixedSizeList
```
reference use
```
listRef
```
.

innerElementType: React.ElementType = "div"

~~innerTagName: string~~
. Deprecated by
```
react-window
```
.
```
itemData: any
```
~~itemKey: function~~
. Handled internally.
```
itemSize: number
```
```
layout: string = "vertical"
```
```
onItemsRendered: function
```
```
onScroll: function
```
```
outerRef: function | createRef object
```

outerElementType: React.ElementType = "div"

~~outerTagName: string~~
. Deprecated by
```
react-window
```
.
```
overscanCount: number = 1
```
```
style: object = null
```
```
useIsScrolling: boolean = false
```
```
width: number | string
```

async: boolean

This option allows making the tree asynchronous; e.g. you will be able to load the branch data on the node opening. All it does under the hood is preserving the tree state between tree buildings on

treeWalker

update, so the user does not see the tree resetting to the default state when the async action is performed.

To see how it works you can check the

AsyncData

story. You can use the

disableAsync

to see what will happen on the async action if the

async

prop is

false

If it is combined with the

placeholder

option, the tree re-building won't be interrupted by showing the placeholder; it will be shown only at the first time the tree is building.

To see how two options interact with each other see the

AsyncDataIdle

story.

children: component

The

Node

component responsible for rendering each node.

It receives the following props:

Inherited from

react-window

Row

component:

```
style: object
```
```
isScrolling: boolean
```
- if
```
useIsScrolling
```
is enabled.

```
Node
```
-specific props:
- All fields of the
```
FixedSizeNodePublicState
```
  object.
- ```
treeData: any
```
  - any data provided via the
```
itemData
```
  property of the
```
FixedSizeTree
```
  component.

placeholder: ReactNode | null

This property receives any react node that will be displayed instead of a tree during the building process. This option should only be used if the tree building process requires too much time (which means you have a really giant amount of data, e.g. about a million nodes).

Setting this option enables the

requestIdleCallback

under the hood for browsers that support this feature. For other browsers the original scenario is applied; no placeholder will be shown.

Using this feature allows avoiding UI freezes; however, it may slightly increase the time spent for the building process.

To see how it works, you can check the BigData story. Use

placeholder

tool to add and remove placeholder.

If you have an asynchronous giant tree and want to use profits of

requestIdleCallback

but don't want placeholder to be shown on the first render (that is probably quite small because all other data will be loaded asynchronously), set

placeholder

null

. No placeholder will be shown on the first render but the

requestIdleCallback

building will be enabled and allow avoiding freezes on tree re-building when tree becomes bigger.

To see how it works you can check the AsyncDataIdle story. It uses the

null

placeholder, so no text is shown for the first build but async requests don't block the UI.

buildingTaskTimeout: number

This option works in tandem with the

placeholder

option. With it, you can set the task timeout for the

requestIdleCallback

. The

buildingTaskTimeout

will be sent directly as the

requestIdleCallback

timeout

option.

listRef: Ref

This option allows you to get the instance of the internal

react-window

list. It is usually unnecessary because all necessary methods are already provided but still can be useful for edge cases.

rowComponent: component

This property receives a custom

Row

component for the

FixedSizeList

that will override the default one. It can be used for adding new functionality.

Row

component receives the following props:

```
index: number
```
```
data: object
```
- the data tree component provides to
```
Row
```
. It contains the following data:
- ```
component: component
```
  - a
```
Node
```
  component to create a React element from.
- ```
getRecordData: function
```
  - a function that gets the record data by
```
index
```
  . It returns a
```
FixedSizeNodePublicState
```
  object.
- ```
treeData: any
```
  - any data provided via the
```
itemData
```
  property of the
```
FixedSizeTree
```
  component.
```
style: object
```
```
isScrolling: boolean
```

* treeWalker()

An iterator function that walks around the tree and yields node data to build an inner representation of the tree. For algorithm details, see TreeWalker section.

The

treeWalker

function should yield the object of the following shape:

```
data: FixedSizeNodeData
```
- this field is mandatory. See
```
FixedSizeNodeData
```
type
for the shape.
```
...
```
- you can add any other data to this object. It will be sent directly to the
```
treeWalker
```
at the step [2] of the execution.

Tree is re-computed on each

treeWalker

change. To avoid unnecessary tree re-computation keep the

treeWalker

memoized (e.g. with

useCallback

hook). If you want to update tree data, send the new version of

treeWalker

to the tree component.

Note that when

treeWalker

is updated no internal state will be shared with the new tree. Everything will be built from scratch.

Methods

The component provides the following methods.

scrollToItem(id: string | symbol, align?: Align): void

The

scrollToItem

method behaves the same as

scrollToItem

from

FixedSizeList

but receives node

id

instead of

index

async recomputeTree(state): void

This method starts the tree traversing to update the internal state of nodes.

It receives

state

object that contains nodes'

id

as keys and update rules as values. Each record traverses a subtree of the specified node (also "owner node") and does not affect other nodes (it also means that if you specify the root node the whole tree will be traversed).

The rules object has the following shape:

```
open: boolean
```
- this rule changes the openness state for the owner node only (subtree nodes are not affected).
```
subtreeCallback(node: object, ownerNode: object): void
```
- this callback runs against each node in the subtree of the owner node (including the owner node as well). It receives the subtree node and the owner node. Changing any property of the subtree node will affect the node state and how it will be displayed (e.g. if you change the node openness state it will be displayed according to the changed state).

The order of rules matters. If you specify the child node rules before the parent node rules, and that rules affect the same property, the parent node

subtreeCallback

will override that property. So if you want to override parent's rules, place children rules after the parent's.

The type of the node objects received by

subtreeCallback

FixedSizeNodePublicState

. See the types description below.

recomputeTree

example

// The tree
const tree = {
  name: 'Root #1',
  id: 'root-1',
  children: [
    {
      children: [
        {id: 'child-2', name: 'Child #2'},
        {id: 'child-3', name: 'Child #3'},
      ],
      id: 'child-1',
      name: 'Child #1',
    },
    {
      children: [{id: 'child-5', name: 'Child #5'}],
      id: 'child-4',
      name: 'Child #4',
    },
  ],
};

// recomputeTree
tree.recomputeTree({
  'root-1': {
    open: false,
    subtreeCallback(node, ownerNode) {
      // Since subtreeCallback affects the ownerNode as well, we can check if the
      // nodes are the same, and run the action only if they aren't
      if (node !== ownerNode) {
        // All nodes of the tree will be closed
        node.isOpen = false;
      }
    },
  },
  // But we want child-4 to be open
  'child-4': true,
});

Types

```
FixedSizeNodeData
```
- value of the
```
data
```
field of the object yielded by the
```
treeWalker
```
function. The shape is the following:
- ```
id
```
  - a unique identifier of the node.
- ```
isOpenByDefault
```
  - a default openness state of the node.
- ```
...
```
  - you can add any number of additional fields to this object. This object without any change will be sent directly to the
```
Node
```
  component. You can also use
```
getRecordData
```
  function to get this object along with the other record data by the index. To describe that data, you have to create a new type that extends the
```
FixedSizeNodeData
```
  type.
```
FixedSizeNodePublicState
```
- the node state available for the
```
Node
```
component and
```
recomputeTree
```
's
```
subtreeCallback
```
function. It has the following shape:
- ```
data: FixedSizeNodeData
```
  .
- ```
isOpen: boolean
```
  - a current openness status of the node.
- ```
setOpen(state: boolean): function
```
  - a function to change the openness state of the node. It receives the new openness state as a
```
boolean
```
  and opens/closes the node accordingly.
```
FixedSizeTreeProps
```
- props that
```
FixedSizeTree
```
component receives. Described in the Props section.
```
FixedSizeTreeState
```
- state that
```
FixedSizeTree
```
component has.

VariableSizeTree

Example

You can also take a look at the very similar example at the Storybook:

import {VariableSizeTree as Tree} from 'react-vtree';

// Tree component can work with any possible tree structure because it uses an
// iterator function that the user provides. Structure, approach, and iterator
// function below is just one of many possible variants.
const tree = {
  name: 'Root #1',
  id: 'root-1',
  children: [
    {
      children: [
        {id: 'child-2', name: 'Child #2'},
        {id: 'child-3', name: 'Child #3'},
      ],
      id: 'child-1',
      name: 'Child #1',
    },
    {
      children: [{id: 'child-5', name: 'Child #5'}],
      id: 'child-4',
      name: 'Child #4',
    },
  ],
};
// This helper function constructs the object that will be sent back at the step
// [2] during the treeWalker function work. Except for the mandatory data
// field you can put any additional data here.
const getNodeData = (node, nestingLevel) => ({
  data: {
    defaultHeight: itemSize, // mandatory
    id: node.id.toString(), // mandatory
    isLeaf: node.children.length === 0,
    isOpenByDefault: true, // mandatory
    name: node.name,
    nestingLevel,
  },
  nestingLevel,
  node,
});
// The treeWalker function runs only on tree re-build which is performed
// whenever the treeWalker prop is changed.
function* treeWalker() {
  // Step [1]: Define the root node of our tree. There can be yielded one or
  // multiple nodes.
  yield getNodeData(tree, 0);
  while (true) {
    // Step [2]: Get the parent component back. It will be the object
    // the getNodeData function constructed, so you can read any data from it.
    const parent = yield;
for (let i = 0; i &lt; parent.node.children.length; i++) {
  // Step [3]: Yielding all the children of the provided component. Then we
  // will return for the step [2] with the first children.
  yield getNodeData(parent.node.children[i], parent.nestingLevel + 1);
}
  }
}
// Node component receives current node height as a prop
const Node = ({data: {isLeaf, name}, height, isOpen, style, setOpen}) => (
  

    {!isLeaf && (
       setOpen(!isOpen)}>
        {isOpen ? '-' : '+'}
      
    )}
    {name}
  
);
const Example = () => (
  
    {Node}
  
);

Props

Props inherited from

VariableSizeList

You can read more about these properties in the

VariableSizeList

documentation.

Since

VariableSizeList

in general inherits properties from the

FixedSizeList

, everything described in the same section for

FixedSizeTree

affects this section. For the rest, there are the following changes:

```
estimatedItemSize: number = 50
```
```
itemSize: (index: number) => number
```
. This property is optional. If it is not provided, the
```
defaultHeight
```
of the specific node will be used. Advanced property; prefer using node state for it.

children

The

Node

component. It is the same as the

FixedSizeTree

's one but receives properties from the

VariableSizeNodePublicState

object.

listRef: Ref

Same as

listRef

FixedSizeTree

rowComponent: component

See

rowComponent

in the

FixedSizeTree

section; the

getRecordData

returns the

VirtualSizeNodePublicState

object.

* treeWalker(refresh: boolean)

An iterator function that walks over the tree. It behaves the same as

FixedSizeTree

treeWalker

. The

data

object should be in the

VariableSizeNodeData

shape.

Methods

The component provides the following methods:

scrollToItem(id: string | symbol, align?: Align): void

The

scrollToItem

method behaves the same as

scrollToItem

from

VariableSizeList

but receives node

id

instead of

index

resetAfterId(id: string | symbol, shouldForceUpdate: boolean = false): void

This method replaces the

resetAfterIndex

method of

VariableSizeList

but works exactly the same. It receives node

id

as a first argument.

async recomputeTree(state): void

See

FixedSizeTree

recomputeTree

description. There are no differences.

Types

All types in this section are the extended variants of

FixedSizeTree

types.

```
VariableSizeNodeData
```
- this object extends
```
FixedSizeNodeData
```
and contains the following additional fields:
- ```
defaultHeight: number
```
  - the default height the node will have.
```
VariableSizeNodePublicState
```
. The node state object. Extends the
```
FixedSizeNodePublicState
```
and contains the following additional fields:
- ```
height: number
```
  - the current height of the node. The node will be displayed with this height.
- ```
resize(newHeight: number, shouldForceUpdate?: boolean): function
```
  - a function to change the height of the node. It receives two parameters:
- ```
newHeight: number
```
  - a new height of the node.
- ```
shouldForceUpdate: boolean
```
  - an optional argument that will be sent directly to the
```
resetAfterIndex
```
  method.
```
VariableSizeTreeProps
```
.
```
VariableSizeTreeState
```
.

TreeWalker algorithm

The

treeWalker

algorithm works in the following way. During the execution, the

treeWalker

function sends a bunch of objects to the tree component which builds an internal representation of the tree. However, for it, the specific order of yieldings should be performed.

The first yielding is always root nodes. They will be the foundation of the whole tree.
Now start a loop where you will receive the parent node and yield all the children of it.
The first yielding of loop iteration should yield an
```
undefined
```
. In exchange, you will receive a node for which you should yield all the children in the same way you've done with the root ones.
When all the children are yielded, and the new iteration of loop is started, you yield
```
undefined
```
again and in exchange receive the next node. It may be:
- a child node if the previous node has children;
- a sibling node if it has siblings;
- a sibling of the elder node.
When the whole tree is finished and algorithm reaches the end, the loop stops. You don't have to finish
```
treeWalker
```
's loop manually.

The example of this algorithm is the following

treeWalker

function:

function* treeWalker() {
  // Here we start our tree by yielding the data for the root node.
  yield getNodeData(rootNode, 0);

  while (true) {
    // Here in the loop we receive the next node whose children should be
    // yielded next.
    const parent = yield;
for (let i = 0; i &lt; parent.node.children.length; i++) {
  // Here we go through the parent's children and yield them to the tree
  // component
  yield getNodeData(parent.node.children[i], parent.nestingLevel + 1);
  // Then the loop iteration is over, and we are going to our next parent
  // node.
}
  }
}

Migrating

2.x.x

3.x.x

If you use

react-vtree

of version 2, it is preferable migrate to the version 3. The third version is quite different under the hood and provides way more optimized approach to the initial tree building and tree openness state change. The most obvious it becomes if you have a giant tree (with about 1 million of nodes).

To migrate to the new version, you have to do the following steps.

1. Migrate

treeWalker

The

treeWalker

was and is the heart of the

react-vtree

. However, now it looks a bit different.

Old

treeWalker

worked for both initial tree building and changing node openness state:

function* treeWalker(refresh) {
  const stack = [];

  stack.push({
    nestingLevel: 0,
    node: rootNode,
  });
  // Go through all the nodes adding children to the stack and removing them
  // when they are processed.
  while (stack.length !== 0) {
    const {node, nestingLevel} = stack.pop();
    const id = node.id.toString();
// Receive the openness state of the node we are working with
const isOpened = yield refresh
  ? {
      id,
      isLeaf: node.children.length === 0,
      isOpenByDefault: true,
      name: node.name,
      nestingLevel,
    }
  : id;

if (node.children.length !== 0 &amp;&amp; isOpened) {
  for (let i = node.children.length - 1; i &gt;= 0; i--) {
    stack.push({
      nestingLevel: nestingLevel + 1,
      node: node.children[i],
    });
  }
}
  }
}

The new

treeWalker

is only for the tree building. The

Tree

component builds and preserves the tree structure internally. See the full description above.

// This function prepares an object for yielding. We can yield an object
// that has `data` object with `id` and `isOpenByDefault` fields.
// We can also add any other data here.
const getNodeData = (node, nestingLevel) => ({
  data: {
    id: node.id.toString(),
    isLeaf: node.children.length === 0,
    isOpenByDefault: true,
    name: node.name,
    nestingLevel,
  },
  nestingLevel,
  node,
});

function* treeWalker() {
  // Here we send root nodes to the component.
  for (let i = 0; i < rootNodes.length; i++) {
    yield getNodeData(rootNodes[i], 0);
  }
  while (true) {
    // Here we receive an object we created via getNodeData function
    // and yielded before. All we need here is to describe its children
    // in the same way we described the root nodes.
    const parentMeta = yield;
for (let i = 0; i &lt; parentMeta.node.children.length; i++) {
  yield getNodeData(
    parentMeta.node.children[i],
    parentMeta.nestingLevel + 1,
  );
}
  }
}

2. Migrate tree components

Components haven't been changed a lot but you may want to add new features like:

3. Migrate

recomputeTree

method

The

recomputeTree

method now receives a list of nodes to change (previously, it was an

opennessState

object). See the full description above.

The most important change is the introduction of the

subtreeCallback

. It is a function that will be applied to each node in the subtree of the specified node. Among other useful things it also allows imitating the behavior of old

useDefaultOpenness

and

useDefaultHeight

options.

Old

recomputeTree

treeInstance.recomputeTree({
  opennessState: {
    'node-1': true,
    'node-2': true,
    'node-3': false,
  },
  refreshNodes: true,
  useDefaultOpenness: false,
});

New

recomputeTree

treeInstance.recomputeTree({
  'node-1': true,
  'node-2': {
    open: true,
    subtreeCallback(node, ownerNode) {
      if (node !== ownerNode) {
        node.isOpen = false;
      }
    },
  },
  'node-3': false,
});

4. Migrate all your

toggle()

calls to

setOpen(boolean)

In the

3.x.x

version node provides a

setOpen

function instead of

toggle

that allows more fine-grained control over the openness state.

Old

toggle

const Node = ({data: {isLeaf, name}, isOpen, style, toggle}) => (
  
    {!isLeaf && (
      
        {isOpen ? '-' : '+'}
      
    )}
    {name}
  
);

New

setOpen

javascript
const Node = ({data: {isLeaf, name}, isOpen, style, setOpen}) => (
  
    {!isLeaf && (
      
        // Imitating the old `toggle` function behavior
         setOpen(!isOpen)}>{isOpen ? '-' : '+'}
      
    )}
    {name}
  
);

5. Migrate all your IDs to string

Using node IDs as keys should improve React rendering performance. However, it means that you won't be able to use

Symbol

as IDs anymore. You should move all your IDs to be strings instead of symbols.

About the developer

Description

Services available

Need anything else?

Contributors list

react-vtree

Installation

Yarn

Usage

FixedSizeTree

Example

Props

Props inherited from FixedSizeList

async: boolean

children: component

placeholder: ReactNode | null

buildingTaskTimeout: number

listRef: Ref

rowComponent: component

* treeWalker()

Methods

scrollToItem(id: string | symbol, align?: Align): void

async recomputeTree(state): void

recomputeTree example

Types

VariableSizeTree

Example

Props

Props inherited from VariableSizeList

children

listRef: Ref

rowComponent: component

* treeWalker(refresh: boolean)

Methods

scrollToItem(id: string | symbol, align?: Align): void

resetAfterId(id: string | symbol, shouldForceUpdate: boolean = false): void

async recomputeTree(state): void

Types

TreeWalker algorithm

Migrating 2.x.x -> 3.x.x

1. Migrate treeWalker

2. Migrate tree components

3. Migrate recomputeTree method

4. Migrate all your toggle() calls to setOpen(boolean)

5. Migrate all your IDs to string

Props inherited from
FixedSizeList

recomputeTree
example

Props inherited from
VariableSizeList

Migrating
2.x.x
->
3.x.x

1. Migrate
treeWalker

3. Migrate
recomputeTree
method

4. Migrate all your
toggle()
calls to
setOpen(boolean)