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How do I check the attribute value of a div in React

I use the JavaScript code below to get and log the attribute value of a div.
I want to rewrite the JavaScript code using React. When I tried doing the same code in React. I get error: e.path.find is not a function
How The Function Works:
First,after clicking mealsEl, e.path.find is used to go through all the child elements of meals EL,
Then it returns the child elements containing the class Name: 'meal-info'
Then it checks if the child element containing class Name 'meal-info' also has an attribute of 'data-meal-id.
Then it logs the value of 'data-meal-id'
const mealsEL = document.getElementById('meals')
mealsEL.addEventListener('click', (e) => {
const mealInfo = e.path.find((item) => {
console.log(item)
if (item.classList) {
return item.classList.contains('meal-info');
} else {
return false;
}
});
console.log(mealInfo)
if (mealInfo) {
const mealID = mealInfo.getAttribute('data-mealid');
getMealByID(mealID);
}
});
<div class="container">
<div id="result-heading"></div>
<div id="meals" class="meals">
<div class="meal">
<img class="meal-img" src="https://source.unsplash.com/random" alt="" style="width:180px; height: 180px;border: solid #000 4px;"/>
<div class="meal-info" >
</div>
</div>
</div>
<div id="single-meal"></div>
</div>
<div id="result-heading"></div>
<div id="meals" class="meals">
<div class="meal">
<img class="meal-img" src="https://source.unsplash.com/random" alt="" style="width:180px; height: 180px;border: solid #000 4px;"/>
<div class="meal-info" >
</div>
</div>
const mealsEL = document.getElementById('meals')
mealsEL.addEventListener('click', (e) => {
const mealInfo = e.path.find((item) => {
if (item.classList) {
console.log(item.classList)
return item.classList.contains("meal-info");
} else {
return false;
}
});
// console.log(mealInfo)
if (mealInfo) {
const mealID = mealInfo.getAttribute('data-mealid');
// getMealByID(mealID);
console.log(mealID)
} else {
console.log('no')
}
});
<div id="meals" class="meals">
<div class="meal">
<img class="meal-img" src="" alt="">
<div class="meal-info" data-mealid="75757">
<h3>Click To Show Data Meal Id</h3>
</div>
</div>
<!-- When mealsEL is clicked, the function uses e.path.find to check if the mealsEl children element contain a className of 'meal-info' and stores the result in the variable `const meal-info`
// The second if statement checks if the child element containing className meal-info has an attribute of 'data-mealid'
// Then the value of data-mealid attribute from the child element is logged to the console
</div> -->
// React Code
const getMealByID = (e) => {
const NativePath = e.nativeEvent()
const mealInfo = NativePath.path.find((item) => {
console.log(mealInfo)
if (item.classList) {
return item.classList.contains('meal-info');
} else {
return false;
}
});
if (mealInfo) {
const mealID = mealInfo.getAttribute('data-mealid');
getMealByID(mealID);
}
}
<div id="meals" className="meals" onClick={getMealByID}>
{meals &&
meals.map((meal) => {
const src = meal.strMealThumb;
const mealID = meal.idMeal;
const alt = meal.strMeal;
const index = meal.idMeal;
// const mealIng = meal.strIngredient1;
const mealIng = [];
for (let i = 1; i <= 20; i++) {
if (meal[`strIngredient${i}`]) {
mealIng.push(
`${meal[`strIngredient${i}`]} - ${meal[`strMeasure${i}`]}`
);
} else {
break;
}
}
return (
<div className="meal" key={index}>
<img className="meal-img" src={src} alt="{alt}" />
<div className="meal-info" data-mealid={mealID}>
<h3>{alt}</h3>
</div>
<h2>{mealIng}</h2>
</div>
);
})}

You are getting the error because you are calling getMealByID with an invalid argument, the function expect an event as argument:
if (mealInfo) {
const mealID = mealInfo.getAttribute('data-mealid');
getMealByID(mealID); //--> mealID is not an event
}
Also I think you can get the mealInfo node using less code:
const getMealByID = e => {
const node = e.target;
const mealInfo = node.querySelector(".meal-info");
if (mealInfo) {
const mealID = mealInfo.getAttribute("data-mealid");
...
}
};

// In order to get the data-mealid attribute value from a div
// by using its parent's element . I had to use
// e.target.getAttribute("data-mealid") on a click event from the parents element.
function App() {
const getMealInfoAttribute = e => {
const mealIDData = e.target.getAttribute("data-mealid")
console.log(mealID)
};
return (
<div id="meals" className="meals" onClick={getMealInfoAttribute}>
<div className="meal" key={index}>
<img className="meal-img" src={src} alt="{alt}" />
<div className="meal-info" data-mealid={mealID}>
<h3>{alt}</h3>
</div>
</div>
);
</div>)
}

How do I give React methods to the onClick handler of an html component?

I'm trying to change the HTML received from a database to respond to custom onClick handlers. Specifically, the HTML I pull has divs called yui-navsets which contain yui_nav page selectors and yui_content page contents. I want to click an li in yui_nav, set that li's class to "selected", set the existing content to display:none, and set the new content to style="".
To do this, I have created a function updateTabs which inputs the index of the chosen yui and the new page number, set that li's class to "selected", set the existing content to display:none, and set the new content to style="". This function works: I tried running updateTabs(2, 3) in componentDidUpdate, and it worked fine, changing the content as requested. I want to assign updateTabs to each of the lis, and I attempt to do so in my componentDidMount after my axios request.
However, I keep getting the error: TypeError: this.updateTabs is not a function. Please help?
Page.js:
import React, { Component } from 'react';
import axios from 'axios';
class Page extends Component {
constructor(props) {
super(props);
this.state = {
innerHTML: "",
pageTags: [],
};
console.log(this.props.url);
}
componentDidMount() {
console.log(this.props.url);
axios
.get(
this.props.db_address + "pages?url=" + this.props.url,
{headers: {"Access-Control-Allow-Origin": "*"}}
)
.then(response => {
this.setState({
innerHTML: response.data[0].html,
pageTags: response.data[1]
});
console.log(response);
// Check for yui boxes, evade the null scenario
var yui_sets = document.getElementsByClassName('yui-navset');
if (yui_sets !== null) {
let yui_set, yui_nav, yui_content;
// Iterate through the navs of each set to find the active tabs
for (var yui_set_count = 0; yui_set_count < yui_sets.length; yui_set_count ++) {
yui_set = yui_sets[yui_set_count];
yui_nav = yui_set.getElementsByClassName('yui-nav')[0].children;
yui_content = yui_set.getElementsByClassName('yui-content')[0].children;
let tab_count;
// Give each nav and tab and appropriate ID for testing purposes
for (tab_count = 0; tab_count < yui_nav.length; tab_count ++) {
yui_nav[tab_count].onclick = function() { this.updateTabs(yui_set_count); }
yui_nav[tab_count].id = "nav-"+ yui_set_count.toString() + "-" + tab_count.toString()
yui_content[tab_count].id = "content-"+ yui_set_count.toString() + "-" + tab_count.toString()
}
}
}
})
.catch(error => {
this.setState({ innerHTML: "ERROR 404: Page not found." })
console.log(error);
});
}
updateTabs(yui_index, tab_index){
// Get all yuis
var yui_sets = document.getElementsByClassName('yui-navset');
let yui_set, yui_nav, yui_content
yui_set = yui_sets[yui_index];
yui_nav = yui_set.getElementsByClassName('yui-nav')[0].children;
yui_content = yui_set.getElementsByClassName('yui-content')[0].children;
// Identify the current active tab
var current_tab_found = false;
var old_index = -1;
while (current_tab_found == false) {
old_index += 1;
if (yui_nav[old_index].className === "selected") {
current_tab_found = true;
}
}
// Identify the new and old navs and contents
var yui_nav_old = yui_nav[old_index]
var yui_nav_new = yui_nav[tab_index]
var yui_content_old = yui_content[old_index]
var yui_content_new = yui_content[tab_index]
// Give the new and old navs and contents their appropriate attributes
yui_nav_old.className = "";
yui_nav_new.className = "selected";
yui_content_old.style = "display:none";
yui_content_new.style = "";
}
render() {
return (
<div className="Page">
<div className="Page-html col-12" dangerouslySetInnerHTML={{__html:this.state.innerHTML}} />
<div className="Page-footer">
<div className="d-flex flex-wrap btn btn-secondary justify-content-around">
{this.state.pageTags.map(function(pageTag){return(
<div className="pd-2" key={pageTag.id}>
{pageTag.name}
</div>
)})}
</div>
<div className="d-flex justify-content-center" >
<div className="p-2">Discuss</div>
<div className="p-2">Rate</div>
<div className="p-2">Edit</div>
</div>
<div className="d-flex justify-content-around App">
<div className="p-2">
Unless otherwise stated, the content
of this page is licensed under <br />
<a href="http://creativecommons.org/licenses/by-sa/3.0/"
target="_blank" rel="noopener noreferrer">
Creative Commons Attribution-ShareAlike 3.0 License
</a>
</div>
</div>
</div>
</div>
)
}
}
export default Page

Instead of function with function keyword use arrow functions and it will be solved as follows
You have
yui_nav[tab_count].onclick = function() { this.updateTabs(yui_set_count); }
But use
yui_nav[tab_count].onclick = () => { this.updateTabs(yui_set_count); }
Use this in componentDidMount method

You have to bind the updateTabs method in the constructor:
constructor(props) {
super(props);
...
this.updateTabs = this.updateTabs.bind(this);
}
You should use arrow functions in order to call this method with the correct contetxt:
yui_nav[tab_count].onclick = () => { this.updateTabs(yui_set_count); }

How to bind onclick handlers to `this` properly on React

Explanation to why this is not a duplicate: My code is already working, I have included as a comment. The question is why the this context change when I include it to click handler function.
I'm attempting a calculator project in React. The goal is to attach onclick handlers to number buttons so the numbers are displayed on the calculator display area. If the handler is written directly to render method it is working, however, if I'm trying from the ComponentDidMount I get an error this.inputDigit is not a function. How do I bind this.inputDigit(digit) properly?
import React from 'react';
import './App.css';
export default class Calculator extends React.Component {
// display of calculator initially zero
state = {
displayValue: '0'
}
//click handler function
inputDigit(digit){
const { displayValue } = this.state;
this.setState({
displayValue: displayValue+String(digit)
})
}
componentDidMount(){
//Get all number keys and attach click handler function
var numberKeys = document.getElementsByClassName("number-keys");
var myFunction = function() {
var targetNumber = Number(this.innerHTML);
return this.inputDigit(targetNumber); // This is not working
};
for (var i = 0; i < numberKeys.length; i++) {
numberKeys[i].onclick = myFunction;
}
}
render() {
const { displayValue } = this.state;
return (
<div className="calculator">
<div className="calculator-display">{displayValue}</div>
<div className="calculator-keypad">
<div className="input-keys">
<div className="digit-keys">
{/*<button className="number-keys" onClick={()=> this.inputDigit(0)}>0</button> This will Work*/}}
<button className="number-keys">0</button>
<button className="number-keys1">1</button>
<button className="number-keys">2</button>
<button className="number-keys">3</button>
<button className="number-keys">4</button>
<button className="number-keys">5</button>
<button className="number-keys">6</button>
<button className="number-keys">7</button>
<button className="number-keys">8</button>
<button className="number-keys">9</button>
</div>
</div>
</div>
</div>
)
}
}

Thats because you are writing it inside a function which is not bound,
Use
var myFunction = function() {
var targetNumber = Number(this.innerHTML);
return this.inputDigit(targetNumber);
}.bind(this);
or
const myFunction = () => {
var targetNumber = Number(this.innerHTML);
return this.inputDigit(targetNumber);
}
After this you need to bind the inputDigit function as well since it also uses setState
//click handler function
inputDigit = (digit) => {
const { displayValue } = this.state;
this.setState({
displayValue: displayValue+String(digit)
})
}
Since you want to use the button text as well, in that case you should use a separate variable in place of this to call the inputDigit function like
class Calculator extends React.Component {
// display of calculator initially zero
state = {
displayValue: '0'
}
//click handler function
inputDigit(digit){
const { displayValue } = this.state;
this.setState({
displayValue: displayValue+String(digit)
})
}
componentDidMount(){
//Get all number keys and attach click handler function
var numberKeys = document.getElementsByClassName("number-keys");
var that = this;
var myFunction = function() {
var targetNumber = Number(this.innerHTML);
console.log(targetNumber);
return that.inputDigit(targetNumber); // This is not working
};
for (var i = 0; i < numberKeys.length; i++) {
numberKeys[i].onclick = myFunction;
}
}
render() {
const { displayValue } = this.state;
return (
<div className="calculator">
<div className="calculator-display">{displayValue}</div>
<div className="calculator-keypad">
<div className="input-keys">
<div className="digit-keys">
{/*<button className="number-keys" onClick={()=> this.inputDigit(0)}>0</button> This will Work*/}
<button className="number-keys">0</button>
<button className="number-keys">1</button>
<button className="number-keys">2</button>
<button className="number-keys">3</button>
<button className="number-keys">4</button>
<button className="number-keys">5</button>
<button className="number-keys">6</button>
<button className="number-keys">7</button>
<button className="number-keys">8</button>
<button className="number-keys">9</button>
</div>
</div>
</div>
</div>
)
}
}
ReactDOM.render(<Calculator/>, document.getElementById('app'))
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react-dom.min.js"></script>
<div id="app"></div>

Bind it in the constructor
constructor(props) {
super(props);
this.inputDigit = this.inputDigit.bind(this);
}

Digging into state in render of Reactjs app components

I cannot reference elements of objects and arrays in a state passed to a subcomponent.
I have not been able to clearly identify the difference between the cases when I cannot reference them in some sub components.
What is the thing I miss?
Sample props of the components is given under the components. Commented.
In that I cannot reference for example, current.main.temp or current.weather[0]. it gives an undefined error:
var Current = React.createClass({
render: function () {
var current = this.props.current;
var dateArray = new Date(current.dt * 1000).toDateString().split(" ");
console.log("datearray: ", dateArray[0]);
var main = current.main;
console.log(main);
return (
<div style={{float: "left", clear:"left"}}>
<div style={{float: "left"}}>
<div>{dateArray[0]}</div>
<div>{dateArray[1]} {dateArray[2]}</div>
<div>{dateArray[3]}</div>
</div>
<div style={{float: "left"}}>
<div>current: {JSON.stringify(current)}</div>
</div>
<div style={{float: "left", clear: "right"}}>
<div>{JSON.stringify(current.weather)}</div>
</div>
</div>
);
},
});
// {"coord":{"lon":32.85,"lat":39.92},"weather":[{"id":801,"main":"Clouds","description":"few clouds","icon":"02d"}],"base":"cmc stations","main":{"temp":28,"pressure":1018,"humidity":34,"temp_min":28,"temp_max":28},"wind":{"speed":2.1},"clouds":{"all":20},"dt":1442483400,"sys":{"type":1,"id":6022,"message":0.0026,"country":"TR","sunrise":1442460682,"sunset":1442505249},"id":323786,"name":"Ankara","cod":200}
however, in that I can reference for example, current.main.temp or current.weather[0]:
var Hour = React.createClass({
render: function () {
var hour = this.props.hour; // is an object.
return (
<div style={{float: "left"}}>
<div>{hour.weather[0].main}</div>
<div>{hour.weather[0].description}</div>
<div><img src={"http://openweathermap.org/img/w/"+hour.weather[0].icon+".png"} /></div>
<div>{hour.main.temp}</div>
<div>{hour.main.temp_min}</div>
<div>{hour.main.temp_max}</div>
<div>{hour.main.humidity}</div>
<div>{new Date(hour.dt * 1000).getHours()} o,clock</div>
</div>
);
}
});
// {"dt":1442437200,"main":{"temp":16.39,"temp_min":14.78,"temp_max":16.39,"pressure":914.76,"sea_level":1026.82,"grnd_level":914.76,"humidity":67,"temp_kf":1.62},"weather":[{"id":800,"main":"Clear","description":"sky is clear","icon":"01n"}],"clouds":{"all":0},"wind":{"speed":1.41,"deg":308.503},"sys":{"pod":"n"},"dt_txt":"2015-09-16 21:00:00"}

It's because of your data structure.
You don't have any property called data in your weather data making current.data.dt and current.data.main be undefined.

How to turn objects in to HTML

How do i get this :
<li>
<div class='myClass1'>myData1</div>
<div class='myClass2'>myData2</div>
<div class='myClass3'>myData3</div>
<div class='myClass4'>myData4</div>
</li>
from this code
var data1 = {"Columns":[{"Title":"Title1","HTMLClass":"g1_Title"},{"Title":"Title2","HTMLClass":"g2_Title"},{"Title":"Title3","HTMLClass":"g3_Title"}],"Rows":[{"Cells":["Cell0","Cell1","Cell2"]},{"Cells":["Cell0","Cell1","Cell2"]},{"Cells":["Cell0","Cell1","Cell2"]},{"Cells":["Cell0","Cell1","Cell2"]},{"Cells":["Cell0","Cell1","Cell2"]},{"Cells":["Cell0","Cell1","Cell2"]},{"Cells":["Cell0","Cell1","Cell2"]},{"Cells":["Cell0","Cell1","Cell2"]},{"Cells":["Cell0","Cell1","Cell2"]},{"Cells":["Cell0","Cell1","Cell2"]},{"Cells":["Cell0","Cell1","Cell2"]},{"Cells":["Cell0","Cell1","Cell2"]},{"Cells":["Cell0","Cell1","Cell2"]},{"Cells":["Cell0","Cell1","Cell2"]},{"Cells":["Cell0","Cell1","Cell2"]},{"Cells":["Cell0","Cell1","Cell2"]},{"Cells":["Cell0","Cell1","Cell2"]},{"Cells":["Cell0","Cell1","Cell2"]},{"Cells":["Cell0","Cell1","Cell2"]},{"Cells":["Cell0","Cell1","Cell2"]}]};
var GridRow = React.createClass({
render: function() {
var data = [], columns;
// puts all the data in to a better structure (ideally the props would have this structure or this manipulation would be done on onReceiveProps)
if(this.props.columns){
for(var ii = 0; ii < this.props.columns.length; ii++){
data.push({
class: this.props.columns[i].HTMLClass,
contents: this.props.Cell[i]
})
}
}
// Its best to map JSX elements and not store them in arrays
columns = data.map(function(col) {
return <div className= + {col.class}> {col.contents} </div>;
});
return (
<div>
<li>
{columns}
</li>
</div>
);
}
});
var GridHead = React.createClass({
render: function() {
if(this.props.data){
var cell = this.props.data.Title;
var htmlClass = this.props.data.HTMLClass;
}
return (
<div className={htmlClass}>{cell}</div>
);
}
});
var GridList = React.createClass({
render: function() {
if(this.props.data){
var header = this.props.data.Columns.map(function (columns) {
return (
<GridHead data={columns} />
);
});
var row = this.props.data.Rows.map(function (row, i) {
return (
<GridRow columns={data1.Columns} cells={row.Cells} key={i} />
);
});
}
return (
<ul>
<li>{header}</li>
{row}
</ul>
);
}
});
var GridBox = React.createClass({
render: function(){
return (
<GridList data={data1} />
);
}
});
The output right now is this
In file "~/Scripts/Grid.jsx": Parse Error: Line 26: XJS value should
be either an expression or a quoted XJS text (at line 26 column 35)
Line: 52 Column:3

As your question initially asked was to do with just the GridRow component and nothing else I have not touched any other component.
Your main problem was you were assigning className = + //something in your GridRow component which isn't the correct way to assign. There were other errors like missing div tags.
Better GridRow
When the component mounts a columndata variable is created and is populated with formatted data using formatData();.
I do not recommend you do data formatting in this component (although it is doable). You should either format your data at a top level component and pass down formatted data or accept data in the correct structure.
My GridRow component to this:
var GridRow = React.createClass({
componentWillMount: function() {
this.columndata = [];
this.formatData();
},
formatData: function() { // Formats prop data into something manageable
if (this.props.columns && this.props.cells) {
for(var ii = 0; ii < this.props.columns.length; ii++){
this.columndata.push({
class: this.props.columns[ii].HTMLClass,
contents: this.props.cells[ii]
})
}
this.forceUpdate(); // Forces a rerender
}
},
componentDidUpdate: function(prevProps, prevState) {
// If this component receives the props late
if (!prevProps.cells && !prevProps.columns) {
this.formatData();
}
},
render: function() {
var columns;
// Its best to map JSX elements and not store them in arrays
columns = this.columndata.map(function(col) {
return <div className={col.class}> {col.contents} </div>;
});
return (
<div>
<li>
{columns}
</li>
</div>
);
}
});
I think it's important to note that you should avoid storing JSX elements in arrays.
I think you were basically on the money, except you were missing classname and div tags.