React.js : 更新嵌套对象的状态
React.js : Updating State of Nested Object
前端 - Front End
单击星号后,我想使用星号的新评级值更新嵌套对象的状态。
我尝试了很多方法,但都没有用,因为状态是不可变的。
Nested State
有人可以建议我如何更新嵌套对象中的值
onStarClicked = (kTypName, subItemId1, newRating) => {
//console.log(subItemId.split("_"));
let evaluation = subItemId1.split("_")[0];
let subItemId = subItemId1.split("_")[1];
console.log(subItemId);
const r = { ...this.state.ratings };
let kT = r.knowledgeTypes;
let sub = '', kTN = '', kIN = '';
kT.map(knowledgeType => {
//console.log(knowledgeType.knowledgeTypeId);
knowledgeType.knowledgeItems.map(knowledgeItem => {
//console.log(knowledgeItem.knowledgeItemId);
knowledgeItem.subItems.map(knowledgeSubItem => {
//console.log(knowledgeSubItem.subItemId);
if (subItemId === knowledgeSubItem.subItemId) {
kTN = knowledgeType.knowledgeTypeName;
kIN = knowledgeItem.knowledgeItemName;
sub = knowledgeSubItem;
if (evaluation === "self") {
sub.evaluation.self.rating = newRating;
}
else if (evaluation === "evaluator") {
sub.evaluation.evaluator.rating = newRating;
}
//alert(evaluation + subItemId + ' ' + newRating);
//return;
}
})
})
});
this.setState({
...this.state,
ratings: {
...this.state.ratings,
knowledgeTypes: [
...this.state.ratings.knowledgeTypes,
this.state.ratings.knowledgeTypes.filter(kt => kt.knowledgeTypeName !== kTN),
{
...this.state.ratings.knowledgeTypes.knowledgeItems.
filter(ki => ki.knowledgeItemName !== kIN),
knowledgeItems: {
...this.state.ratings.knowledgeTypes.knowledgeItems.subItems.
filter(si => si.subItemId !== subItemId),
sub
}
}]
}
});
}
您基本上必须创建一个新的 knowledgeTypes
空数组,并使用当前状态找到您需要使用 Object.keys/map/filter
函数更改的状态项。
您将在变量中使用当前状态并仅修改该变量。您可能不会以任何方式弄乱实际状态对象。
完成后,只需将其附加到空数组即可。然后你可以 setState() 将新数组设置为实际状态 属性.
class MyComponent extends React.Component {
constructor(props) {
super(props);
this.state = {
financialYear: "2019-20",
quarter: "Q1",
isCurrentQuarter: true,
knowledgeTypes: [
{
knowledgeTypeName: "Technology",
knowledgeItems: [
{
knowledgeItemName: "Java",
subItems: [
{
subItemId: "2",
subItemName: "Collections",
evaluation: {
self: {
ntnet: "Joe",
rating: 1,
isEditable: true
}
}
}
]
}
]
}
]
};
}
handleClick = e => {
const { knowledgeTypes } = this.state;
// transformation
const itemToChange = knowledgeTypes.map(item => {
if (item.knowledgeTypeName === "Technology") {
return item;
}
});
const currItems = itemToChange[0].knowledgeItems[0].subItems;
const subItem = currItems.map(item => {
if (item.subItemId === "2") {
return item;
}
});
const person = subItem[0].evaluation;
person.self.rating = 55; //change
const newKnowledgeTypes = [];
knowledgeTypes.map(item => {
if (item.knowledgeTypeName === "Technology") {
newKnowledgeTypes.push(itemToChange);
}
newKnowledgeTypes.push(item);
});
this.setState({
knowledgeTypes: newKnowledgeTypes
});
console.log(this.state);
};
render() {
return (
<div>
MyComponent
<button onClick={this.handleClick}>Hello</button>
</div>
);
}
}
可以在 https://codesandbox.io/s/musing-dew-8r2vk 上找到沙盒。
注意:建议您不要使用嵌套状态对象,因为状态对象是更轻量级的东西,因此它们没有性能方面的考虑。
import React, { Component } from 'react';
import Auxilary from '../../../hoc/Auxilary/auxilary';
import KnowledgeItems from '../KnowledgeItems/KnowledgeItems';
import Tabs from 'react-bootstrap/Tabs';
import Tab from 'react-bootstrap/Tab';
import knowledge from '../../../assests/staticdata.json';
import './QuarterLog.css';
class QuarterLog extends Component {
constructor() {
super();
this.state = {
"financialYear": "",
"quarter": "",
"isCurrentQuarter": "",
"knowledgeTypes": []
}
}
onStarClicked = (kTypName, kItemName, subItemIdName, newRating) => {
let evaluation = subItemIdName.split("_")[0];
let subItemId = subItemIdName.split("_")[1];
const { knowledgeTypes } = this.state;
// transformation
let knowledgeTypeToChange = knowledgeTypes.map(kType => {
if (kType.knowledgeTypeName === kTypName) {
return kType;
}
});
knowledgeTypeToChange = knowledgeTypeToChange.filter(function (element) {
return element !== undefined;
});
console.log(knowledgeTypeToChange[0]);
let knowledgeItemToChange = knowledgeTypeToChange[0].knowledgeItems.map(item => {
if (item.knowledgeItemName === kItemName) {
return item;
}
});
knowledgeItemToChange = knowledgeItemToChange.filter(function (element) {
return element !== undefined;
});
let knowledgeSubItem = knowledgeItemToChange[0].subItems.map(subItem => {
if (subItem.subItemId === subItemId) {
return subItem;
}
});
knowledgeSubItem = knowledgeSubItem.filter(function (element) {
return element !== undefined;
});
console.log(knowledgeSubItem);
let personEvaluations = knowledgeSubItem[0].evaluation;
if (evaluation === "self") {
personEvaluations.self.rating = newRating.toString(); //change
}
else if (evaluation === "evaluator") {
personEvaluations.evaluator.rating = newRating.toString(); //change
}
const newKnowledgeTypes = [];
knowledgeTypes.map(item => {
if (item.knowledgeTypeName === kTypName) {
newKnowledgeTypes.push(knowledgeTypeToChange[0]);
}
else
newKnowledgeTypes.push(item);
});
this.setState({
knowledgeTypes: newKnowledgeTypes
});
console.log(this.state);
}
componentDidMount() {
// TODO: remove staticdata.js and call REST API and set the response in state
this.setState({
...this.state,
"financialYear": knowledge.financialYear,
"quarter": knowledge.quarter,
"isCurrentQuarter": knowledge.isCurrentQuarter,
"knowledgeTypes": knowledge.knowledgeTypes
})
}
onSubmitRatings = () => {
console.log(this.state);
}
render() {
let data = knowledge; //remove this code, once REST API is implemented
const posts = this.state.knowledgeTypes.map(knowledgeType => {
return (
<Tab key={knowledgeType.knowledgeTypeName} eventKey={knowledgeType.knowledgeTypeName}
title={knowledgeType.knowledgeTypeName}>
<KnowledgeItems
kTypeName={knowledgeType.knowledgeTypeName}
kItems={knowledgeType.knowledgeItems}
ratings={this.state.ratings}
onstarclicked={this.onStarClicked}
/>
</Tab>)
});
return (
<Auxilary>
<div className="d-flex justify-content-between flex-wrap flex-md-nowrap align-items-center pt-3 pb-2 mb-3 border-bottom">
<div><h1>Financial Year : {data.financialYear}</h1></div>
<div><h2>Quarter : {data.quarter}</h2></div>
</div>
<div>
<Tabs defaultActiveKey="Domain" id="uncontrolled-tab-example">
{posts}
</Tabs>
</div>
<button onClick={this.onSubmitRatings}> Submit </button>
</Auxilary>
);
}
}
export default QuarterLog;
前端 - Front End 单击星号后,我想使用星号的新评级值更新嵌套对象的状态。
我尝试了很多方法,但都没有用,因为状态是不可变的。
Nested State
有人可以建议我如何更新嵌套对象中的值
onStarClicked = (kTypName, subItemId1, newRating) => {
//console.log(subItemId.split("_"));
let evaluation = subItemId1.split("_")[0];
let subItemId = subItemId1.split("_")[1];
console.log(subItemId);
const r = { ...this.state.ratings };
let kT = r.knowledgeTypes;
let sub = '', kTN = '', kIN = '';
kT.map(knowledgeType => {
//console.log(knowledgeType.knowledgeTypeId);
knowledgeType.knowledgeItems.map(knowledgeItem => {
//console.log(knowledgeItem.knowledgeItemId);
knowledgeItem.subItems.map(knowledgeSubItem => {
//console.log(knowledgeSubItem.subItemId);
if (subItemId === knowledgeSubItem.subItemId) {
kTN = knowledgeType.knowledgeTypeName;
kIN = knowledgeItem.knowledgeItemName;
sub = knowledgeSubItem;
if (evaluation === "self") {
sub.evaluation.self.rating = newRating;
}
else if (evaluation === "evaluator") {
sub.evaluation.evaluator.rating = newRating;
}
//alert(evaluation + subItemId + ' ' + newRating);
//return;
}
})
})
});
this.setState({
...this.state,
ratings: {
...this.state.ratings,
knowledgeTypes: [
...this.state.ratings.knowledgeTypes,
this.state.ratings.knowledgeTypes.filter(kt => kt.knowledgeTypeName !== kTN),
{
...this.state.ratings.knowledgeTypes.knowledgeItems.
filter(ki => ki.knowledgeItemName !== kIN),
knowledgeItems: {
...this.state.ratings.knowledgeTypes.knowledgeItems.subItems.
filter(si => si.subItemId !== subItemId),
sub
}
}]
}
});
}
您基本上必须创建一个新的 knowledgeTypes
空数组,并使用当前状态找到您需要使用 Object.keys/map/filter
函数更改的状态项。
您将在变量中使用当前状态并仅修改该变量。您可能不会以任何方式弄乱实际状态对象。
完成后,只需将其附加到空数组即可。然后你可以 setState() 将新数组设置为实际状态 属性.
class MyComponent extends React.Component {
constructor(props) {
super(props);
this.state = {
financialYear: "2019-20",
quarter: "Q1",
isCurrentQuarter: true,
knowledgeTypes: [
{
knowledgeTypeName: "Technology",
knowledgeItems: [
{
knowledgeItemName: "Java",
subItems: [
{
subItemId: "2",
subItemName: "Collections",
evaluation: {
self: {
ntnet: "Joe",
rating: 1,
isEditable: true
}
}
}
]
}
]
}
]
};
}
handleClick = e => {
const { knowledgeTypes } = this.state;
// transformation
const itemToChange = knowledgeTypes.map(item => {
if (item.knowledgeTypeName === "Technology") {
return item;
}
});
const currItems = itemToChange[0].knowledgeItems[0].subItems;
const subItem = currItems.map(item => {
if (item.subItemId === "2") {
return item;
}
});
const person = subItem[0].evaluation;
person.self.rating = 55; //change
const newKnowledgeTypes = [];
knowledgeTypes.map(item => {
if (item.knowledgeTypeName === "Technology") {
newKnowledgeTypes.push(itemToChange);
}
newKnowledgeTypes.push(item);
});
this.setState({
knowledgeTypes: newKnowledgeTypes
});
console.log(this.state);
};
render() {
return (
<div>
MyComponent
<button onClick={this.handleClick}>Hello</button>
</div>
);
}
}
可以在 https://codesandbox.io/s/musing-dew-8r2vk 上找到沙盒。
注意:建议您不要使用嵌套状态对象,因为状态对象是更轻量级的东西,因此它们没有性能方面的考虑。
import React, { Component } from 'react';
import Auxilary from '../../../hoc/Auxilary/auxilary';
import KnowledgeItems from '../KnowledgeItems/KnowledgeItems';
import Tabs from 'react-bootstrap/Tabs';
import Tab from 'react-bootstrap/Tab';
import knowledge from '../../../assests/staticdata.json';
import './QuarterLog.css';
class QuarterLog extends Component {
constructor() {
super();
this.state = {
"financialYear": "",
"quarter": "",
"isCurrentQuarter": "",
"knowledgeTypes": []
}
}
onStarClicked = (kTypName, kItemName, subItemIdName, newRating) => {
let evaluation = subItemIdName.split("_")[0];
let subItemId = subItemIdName.split("_")[1];
const { knowledgeTypes } = this.state;
// transformation
let knowledgeTypeToChange = knowledgeTypes.map(kType => {
if (kType.knowledgeTypeName === kTypName) {
return kType;
}
});
knowledgeTypeToChange = knowledgeTypeToChange.filter(function (element) {
return element !== undefined;
});
console.log(knowledgeTypeToChange[0]);
let knowledgeItemToChange = knowledgeTypeToChange[0].knowledgeItems.map(item => {
if (item.knowledgeItemName === kItemName) {
return item;
}
});
knowledgeItemToChange = knowledgeItemToChange.filter(function (element) {
return element !== undefined;
});
let knowledgeSubItem = knowledgeItemToChange[0].subItems.map(subItem => {
if (subItem.subItemId === subItemId) {
return subItem;
}
});
knowledgeSubItem = knowledgeSubItem.filter(function (element) {
return element !== undefined;
});
console.log(knowledgeSubItem);
let personEvaluations = knowledgeSubItem[0].evaluation;
if (evaluation === "self") {
personEvaluations.self.rating = newRating.toString(); //change
}
else if (evaluation === "evaluator") {
personEvaluations.evaluator.rating = newRating.toString(); //change
}
const newKnowledgeTypes = [];
knowledgeTypes.map(item => {
if (item.knowledgeTypeName === kTypName) {
newKnowledgeTypes.push(knowledgeTypeToChange[0]);
}
else
newKnowledgeTypes.push(item);
});
this.setState({
knowledgeTypes: newKnowledgeTypes
});
console.log(this.state);
}
componentDidMount() {
// TODO: remove staticdata.js and call REST API and set the response in state
this.setState({
...this.state,
"financialYear": knowledge.financialYear,
"quarter": knowledge.quarter,
"isCurrentQuarter": knowledge.isCurrentQuarter,
"knowledgeTypes": knowledge.knowledgeTypes
})
}
onSubmitRatings = () => {
console.log(this.state);
}
render() {
let data = knowledge; //remove this code, once REST API is implemented
const posts = this.state.knowledgeTypes.map(knowledgeType => {
return (
<Tab key={knowledgeType.knowledgeTypeName} eventKey={knowledgeType.knowledgeTypeName}
title={knowledgeType.knowledgeTypeName}>
<KnowledgeItems
kTypeName={knowledgeType.knowledgeTypeName}
kItems={knowledgeType.knowledgeItems}
ratings={this.state.ratings}
onstarclicked={this.onStarClicked}
/>
</Tab>)
});
return (
<Auxilary>
<div className="d-flex justify-content-between flex-wrap flex-md-nowrap align-items-center pt-3 pb-2 mb-3 border-bottom">
<div><h1>Financial Year : {data.financialYear}</h1></div>
<div><h2>Quarter : {data.quarter}</h2></div>
</div>
<div>
<Tabs defaultActiveKey="Domain" id="uncontrolled-tab-example">
{posts}
</Tabs>
</div>
<button onClick={this.onSubmitRatings}> Submit </button>
</Auxilary>
);
}
}
export default QuarterLog;