CODEWITHSUNDEEP
javascriptreactjs
totalnoob
totalnoob

Reputation: 2741

converting a function into jsx

I've got two functions, one to parse an html string to get its headers into an array 

const str = "<h1>test-1<h1><h2>test1-1<h2><h3>test1-1-1</h3><h1>test1-2<h1><h2>test1-2-1</h2><h3>test1-2-2</h3><h1>test-2</h1><h1>test-3</h1><h1>test-4</h1>
"
const wrapper = document.createElement('div');
wrapper.innerHTML = str.trim();

let tree = [];
let leaf = null;

for (const node of wrapper.querySelectorAll("h1, h2, h3, h4, h5, h6"))
{
    const nodeLevel = parseInt(node.tagName[1]);
    const newLeaf = { level: nodeLevel, text: node.textContent, children: [], parent: leaf };

    while (leaf && newLeaf.level <= leaf.level)
        leaf = leaf.parent;

    if (!leaf)
        tree.push(newLeaf);
    else
        leaf.children.push(newLeaf);

    leaf = newLeaf;
}

and another to parse those headers into a list for a table of contents feature

const ol = document.createElement("ol");

(function makeOl(ol, leaves)
{
    for (const leaf of leaves)
    {
        const li = document.createElement("li");
        li.appendChild(new Text(leaf.text));

        if (leaf.children.length > 0)
        {
            const subOl = document.createElement("ol");
            makeOl(subOl, leaf.children);
            li.appendChild(subOl);
        }

        ol.appendChild(li);
    }
})(ol, tree);

it outputs a string like this

"<ol><li>test-1<ol><li>test1-1<ol><li>test1-1-1</li></ol></li><li>test1-2<ol><li>test1-2-1</li><li>test1-2-2</li></ol></li></ol></li><li>test-2</li><li>test-3</li><li>test-4</li></ol>"

which renders to something like

  1. test-1
    1. test1-1
      1. test1-1-1
    2. test1-2
      1. test1-2-1
      2. test1-2-2
  2. test-2
  3. test-3
  4. test-4

I'm still getting used to the jsx part of React and I'm wondering how to convert that function so that the ol's and li's are React/jsx elements rather than a string of raw html as that'd require another step to render eg.

<div dangerouslySetInnerHTML={{__html: olString}} />

the way I'm using to using jsx with arrays is something like this

const list = tree.map((headers) => <li>{headers.value}</li>)
<div><ul>{list}</ul></div>

Upvotes: 0

Views: 1005

Answers (2)

Luke
Luke

Reputation: 8407

You can always use React.createElement

e.g.

React.createElement('div', null, `Hello ${this.props.toWhat}`);

But, best practice might be something like this.

// reusable Tree component
export default class Tree extends Component {

  static propTypes = {
    children: PropTypes.array.isRequired
  }

  render() {

    const { children } = this.props

    return (
      <ol>
        {children.map(leaf =>
          <li key={leaf.id}>
            <span>{leaf.text}</span>
            {leaf.children && <Tree children={leaf.children}/>}
          </li>
        )}
      </ol>
    )
  }
}

// (re)use it 
function render() {
  return (
    <Tree children={ tree } />
  );
}

You could even make the HTML Elements variable.

<Tree children={ tree } listNode="ul" listElementNode="li" />

then in the Tree component

function render() {
    const {listNode: UL, listElementNode: LI} = this.props;
    return (<UL></UL>);
}

Upvotes: 2

DoXicK
DoXicK

Reputation: 4812

Currently, you have a recursive function (makeOl), which i replaced with a renderLeaf function:

a way to render this would be:

class Tree extends React.Component {
  render() {
    let leafs = this.props.children
    return (
      <React.Fragment>
        {leafs.map(this.renderLeaf)}
      </React.Fragment>
    )
  }
  renderLeaf(leaf) {
    return (
      <ol>
        <li>
          {leaf.text}
          {leaf.children && leaf.children.map(this.renderLeaf)}
        </li>
      </ol>
    )
  }
}

you can then use this as: <Tree children={tree} />

Upvotes: 1

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