How to draw the NESTED SETS tree?

Question

JavaScript

Hello!
I have a nested sets tree. It is necessary to draw this tree, with the ability to reveal / hide parent elements (similar to the project folder hierarchy in ide and editors)

Answer 1

We need two things: a function that will turn the nested set into a real tree (in the sense that it will make a nested one from a flat structure) and a recursive component that this tree will display. For example .

spoiler

const createTreeFromNestedSet = arr =>
  [...arr].sort((a, b) => a.left - b.left).reduce((tree, n) => {
    let curr = null;
    let next = tree;

    while (next) {
      curr = next;
      next = curr.children.find(c => c.left < n.left && c.right > n.right);
    }

    curr.children.push({ ...n, children: [] });

    return tree;
  }, { children: [] }).children[0];


const NestedSetTreeItem = ({ item }) => {
  const [ showChildren, setShowChildren ] = React.useState(false);
  const onClick = () => setShowChildren(v => !v);

  return (
    <div className="tree-item">
      <span>{item.title}: {item.left} - {item.right}</span>
      {item.children.length !== 0 ? (
        <React.Fragment>
          <button onClick={onClick}>{showChildren ? '-' : '+'}</button>
          <div className={showChildren ? '' : 'hidden'}>
            {item.children.map(n => <NestedSetTreeItem key={n.id} item={n} />)}
          </div>
        </React.Fragment>
      ) : null}
    </div>
  );
};

const NestedSetTree = ({ data }) => {
  const tree = React.useMemo(() => createTreeFromNestedSet(data), [ data ]);

  return <NestedSetTreeItem item={tree} />;
};


const data = [
  { title: 'Clothing', left: 1, right: 22 },
  { title: 'Men\'s', left: 2, right: 9 },
  { title: 'Women\'s', left: 10, right: 21 },
  { title: 'Suits', left: 3, right: 8 },
  { title: 'Slacks', left: 4, right: 5 },
  { title: 'Jackets', left: 6, right: 7 },
  { title: 'Dresses', left: 11, right: 16 },
  { title: 'Skirts', left: 17, right: 18 },
  { title: 'Blouses', left: 19, right: 20 },
  { title: 'Evening Gowns', left: 12, right: 13 },
  { title: 'Sun Dresses', left: 14, right: 15 },
].map((n, i) => ({ ...n, id: i + 1 }));

ReactDOM.render(<NestedSetTree data={data} />, document.getElementById('app'));

<div id="app"></div>

Answer 2

and the search was turned off for non-payment?