i'm new to react and i'm trying to convert this class based component to a functionnal component but i get an error of state, how can i convert it please ? This is my components :)
Thank you
CodePudding user response：
In this example, it is quite straight forward as there are no component life cycle methods. You can just define all the methods in the function, and return the component.
function Demo() {
const [state, setState] = React.useState({
expandedKeys: [],
autoExpandParent: true,
checkedKeys: [],
allCheckedKeys: [],
selectedKeys: [],
newTreeView: false,
newTreeData: []
});
const onExpand = (expandedKeys) => {
console.log("onExpand", expandedKeys);
// if not set autoExpandParent to false, if children expanded, parent can not collapse.
// or, you can remove all expanded children keys.
setState({
...state,
expandedKeys,
autoExpandParent: false
});
};
const onCheck = (checkedKeys, e) => {
const allCheckedKeys = [...checkedKeys, ...e.halfCheckedKeys];
console.log("onCheck", allCheckedKeys);
console.log(createNewTreeData(treeData, allCheckedKeys));
setState((prevState) => ({
...prevState,
allCheckedKeys,
checkedKeys
}));
};
const onSelect = (selectedKeys, info) => {
console.log("onSelect", info);
setState({ ...state, selectedKeys });
};
const renderTreeNodes = (data) =>
data.map((item) => {
if (item.children) {
return (
<TreeNode title={item.title} key={item.key} dataRef={item}>
{renderTreeNodes(item.children)}
</TreeNode>
);
}
return <TreeNode {...item} />;
});
const createTree = () => {
setState((prevState) => ({
...prevState,
newTreeView: true,
newTreeData: createNewTreeData(treeData, prevState.allCheckedKeys)
}));
};
return (
<>
<Tree
checkable
onExpand={onExpand}
expandedKeys={state.expandedKeys}
autoExpandParent={state.autoExpandParent}
onCheck={onCheck}
checkedKeys={state.checkedKeys}
onSelect={onSelect}
selectedKeys={state.selectedKeys}
>
{renderTreeNodes(treeData)}
</Tree>
<button onClick={createTree}>Validate</button>
{state.newTreeView && <Tree>{renderTreeNodes(state.newTreeData)}</Tree>}
</>
);
}
CodePudding user response：
import React, { useState } from 'react';
import ReactDOM from 'react-dom';
import 'antd/dist/antd.css';
import './index.css';
import { Tree } from 'antd';
const treeData = [
{
title: '0-0',
key: '0-0',
children: [
{
title: '0-0-0',
key: '0-0-0',
children: [
{
title: '0-0-0-0',
key: '0-0-0-0',
},
{
title: '0-0-0-1',
key: '0-0-0-1',
},
{
title: '0-0-0-2',
key: '0-0-0-2',
},
],
},
{
title: '0-0-1',
key: '0-0-1',
children: [
{
title: '0-0-1-0',
key: '0-0-1-0',
},
{
title: '0-0-1-1',
key: '0-0-1-1',
},
{
title: '0-0-1-2',
key: '0-0-1-2',
},
],
},
{
title: '0-0-2',
key: '0-0-2',
},
],
},
{
title: '0-1',
key: '0-1',
children: [
{
title: '0-1-0-0',
key: '0-1-0-0',
},
{
title: '0-1-0-1',
key: '0-1-0-1',
},
{
title: '0-1-0-2',
key: '0-1-0-2',
},
],
},
{
title: '0-2',
key: '0-2',
},
];
const Demo = () => {
const [expandedKeys, setExpandedKeys] = useState(['0-0-0', '0-0-1']);
const [checkedKeys, setCheckedKeys] = useState(['0-0-0']);
const [selectedKeys, setSelectedKeys] = useState([]);
const [autoExpandParent, setAutoExpandParent] = useState(true);
const onExpand = (expandedKeysValue) => {
console.log('onExpand', expandedKeysValue); // if not set autoExpandParent to false, if children expanded, parent can not collapse.
// or, you can remove all expanded children keys.
setExpandedKeys(expandedKeysValue);
setAutoExpandParent(false);
};
const onCheck = (checkedKeysValue) => {
console.log('onCheck', checkedKeysValue);
setCheckedKeys(checkedKeysValue);
};
const onSelect = (selectedKeysValue, info) => {
console.log('onSelect', info);
setSelectedKeys(selectedKeysValue);
};
return (
<Tree
checkable
onExpand={onExpand}
expandedKeys={expandedKeys}
autoExpandParent={autoExpandParent}
onCheck={onCheck}
checkedKeys={checkedKeys}
onSelect={onSelect}
selectedKeys={selectedKeys}
treeData={treeData}
/>
);
};
ReactDOM.render(<Demo />, document.getElementById('container'));
CodePudding user response：
I have updated the code using ES6 arrow functions resulting in shorter and simpler code than traditional functional components.
import React,{useState} from "react";
import ReactDOM from "react-dom";
import "antd/dist/antd.css";
import "./index.css";
import { Tree } from "antd";
const { TreeNode } = Tree;
const treeData = [
{
title: "0-0",
key: "0-0",
children: [
{
title: "0-0-0",
key: "0-0-0",
children: [
{ title: "0-0-0-0", key: "0-0-0-0" },
{ title: "0-0-0-1", key: "0-0-0-1" },
{ title: "0-0-0-2", key: "0-0-0-2" }
]
},
{
title: "0-0-1",
key: "0-0-1",
children: [
{ title: "0-0-1-0", key: "0-0-1-0" },
{ title: "0-0-1-1", key: "0-0-1-1" },
{ title: "0-0-1-2", key: "0-0-1-2" }
]
},
{
title: "0-0-2",
key: "0-0-2"
}
]
},
{
title: "0-1",
key: "0-1",
children: [
{ title: "0-1-0-0", key: "0-1-0-0" },
{ title: "0-1-0-1", key: "0-1-0-1" },
{ title: "0-1-0-2", key: "0-1-0-2" }
]
},
{
title: "0-2",
key: "0-2"
}
];
const createNewTreeData = (treeData, checkedKeys) => {
return treeData.reduce((acc, treeDataItem) => {
if (checkedKeys.includes(treeDataItem.key)) {
if (treeDataItem.children) {
acc.push({
...treeDataItem,
children: createNewTreeData(treeDataItem.children, checkedKeys)
});
} else {
acc.push(treeDataItem);
}
}
return acc;
}, []);
};
const Demo =()=> {
const [state,setState] = useState({
expandedKeys: [],
autoExpandParent: true,
checkedKeys: [],
allCheckedKeys: [],
selectedKeys: [],
newTreeView: false,
newTreeData: []
});
const onExpand = (expandedKeys) => {
console.log("onExpand", expandedKeys);
// if not set autoExpandParent to false, if children expanded, parent can not collapse.
// or, you can remove all expanded children keys.
setState({
expandedKeys,
autoExpandParent: false
});
};
const onCheck = (checkedKeys, e) => {
const allCheckedKeys = [...checkedKeys, ...e.halfCheckedKeys];
console.log("onCheck", allCheckedKeys);
console.log(createNewTreeData(treeData, allCheckedKeys));
setState((prevState) => ({
...prevState,
allCheckedKeys,
checkedKeys
}));
};
const onSelect = (selectedKeys, info) => {
console.log("onSelect", info);
setState({ selectedKeys });
};
const renderTreeNodes = (data) =>
data.map((item) => {
if (item.children) {
return (
<TreeNode title={item.title} key={item.key} dataRef={item}>
{renderTreeNodes(item.children)}
</TreeNode>
);
}
return <TreeNode {...item} />;
});
const createTree = () => {
setState((prevState) => ({
...prevState,
newTreeView: true,
newTreeData: createNewTreeData(treeData, prevState.allCheckedKeys)
}));
};
return (
<>
<Tree
checkable
onExpand={onExpand}
expandedKeys={state.expandedKeys}
autoExpandParent={state.autoExpandParent}
onCheck={onCheck}
checkedKeys={state.checkedKeys}
onSelect={onSelect}
selectedKeys={state.selectedKeys}
>
{renderTreeNodes(treeData)}
</Tree>
<button onClick={createTree}>Validate</button>
{state.newTreeView && (
<Tree>{renderTreeNodes(state.newTreeData)}</Tree>
)}
</>
);
}
ReactDOM.render(<Demo />, document.getElementById("container"));