People.ai

listToTree.js

const data = [
  { id: 1, name: "San Francisco", parent: 5 },
  { id: 2, name: "Los Angeles", parent: 5 },
  { id: 3, name: "San Diego", parent: 5 },
  { id: 4, name: "Tucson", parent: 7 },
  { id: 5, name: "California", parent: 6 },
  { id: 6, name: "USA", parent: null },
  { id: 7, name: "Arizona", parent: 6 },
  { id: 8, name: "Tukey", parent: null },
  { id: 9, name: "Istanbul", parent: 8 },
  { id: 10, name: "Besiktas", parent: 9 },
  { id: 11, name: "Kadikoy", parent: 9 },
  { id: 12, name: "Czechia", parent: null },
  { id: 13, name: "Prague", parent: 12 },
  { id: 14, name: "Karlin", parent: 13 },
  { id: 15, name: "Brno", parent: 12 }
];

const convertToTree = (data) => {
  let tree = { children: [] };

  while (data.length > 0) {
    data.map((item, index) => {
      if (item.parent === null) {
        tree = { ...tree, children: [...tree.children, ...[item]] };
        data.splice(index, 1);
      } else {
        const handleChildren = (tree) =>
          (tree.children || []).map((child) => {
            if (child.id === item.parent) {
              child.children = [...(child.children || []), ...[item]];
              data.splice(index, 1);
            } else {
              handleChildren(child);
            }

            return child;
          });

        tree.children = handleChildren(tree);
      }
      return item;
    });
    console.log(data.length);
  }
  return tree;
};

console.log(JSON.stringify(convertToTree(data), {}, Infinity));