在react-js中的insertAdjacentHTML中添加onclick或eventListener

Question

I am building a simple react app for learning purpose, I just started learning react-js, I was trying to add paragraph dynamically on user action and it worked perfectly But I want to add an onClick event in insertAdjacentHTML (basically innerHTML).

But onclick event is not working in innerHTML

app.js

const addParagraph = () => {
    var paragraphSpace = document.getElementById('container')
    paragraphSpace.insertAdjacentHTML('beforeend', `<p>I am dynamically created paragraph for showing purpose<p> <span id="delete-para" onClick={deleteParagraph(this)}>Delete</span>`
}

const deleteParagraph = (e) => {
    document.querySelector(e).parent('div').remove();
}

class App extends React.Component {
    render() {
        return (
            <div>
                <div onClick={addParagraph}>
                     Click here to Add Paragraph
                </div>

                <div id="container"></div>
            </div>
        )
    }
}

What I am trying to do?

User will be able to add multiple paragraphs and I am trying to add a delete button on every paragraph so user can delete particular paragraph

I have also tried with eventListener like:-

const deleteParagraph = () => {
    document.querySelector('#delete').addEventListener("click", "#delete", 
    function(e) {
          e.preventDefault();
          document.querySelector(this).parent('div').remove();
        })
}

But It said

deleteParagraph is not defined

I also tried to wrap deleteParagraph in componentDidMount() But it removes everything from the window.

Any help would be much Appreciated. Thank You.

Answer 1

insertAdjecentHTML should not be used in javascripts frameworks because they work on entirely different paradigm. React components are rerendered every time you change a component state. So you want to manipulate look of your component by changing its state

Solution: In constructor initialize your component's state which you will change later on button click. Initial state is array of empty paragraphs.

constructor() {
    super()
    this.state = {
      paragraphs:[]
    }
  }

And alter that state on button click - like this:

<div onClick={addParagraph}>

Add Paragraph function

const addParagraph = () =>{
   this.state = this.state.push('New paragraph')
}

Rendering paragraphs

<div id="container">
this.state.paragraphs.map(paragraph =>{
   <p>{paragraph}</p>
})
</div>

Additional tip for ReactJS in 2022 - use Functional components instead of Class components

Answer 2

Do not manipulate the DOM directly, let React handle DOM changes instead. Here's one way to implement it properly.

class App extends React.Component {
  state = { paragraphs: [] };

  addParagraph = () => {
    // do not mutate the state directly, make a clone
    const newParagraphs = this.state.paragraphs.slice(0);

    // and mutate the clone, add a new paragraph
    newParagraphs.push('I am dynamically created paragraph for showing purpose');

    // then update the paragraphs in the state
    this.setState({ paragraphs: newParagraphs });
  };

  deleteParagraph = (index) => () => {
    // do not mutate the state directly, make a clone
    const newParagraphs = this.state.paragraphs.slice(0);

    // and mutate the clone, delete the current paragraph
    newParagraphs.splice(index, 1);

    // then update the paragraphs in the state
    this.setState({ paragraphs: newParagraphs });
  };

  render() {
    return (
      <div>
        <div onClick={this.addParagraph}>Click here to Add Paragraph</div>
        <div id="container">
          {this.state.paragraphs.map((paragraph, index) => (
            <>
              <p>{paragraph}</p>
              <span onClick={this.deleteParagraph(index)}>Delete</span>
            </>
          ))}
        </div>
      </div>
    );
  }
}