create tres structure

tree1.js

// sorted data
var resData = [
  { id: "1", level: 1 },
  { id: "2", level: 1 },
  { id: "2-1", level: 2 },
  { id: "2-1-1", level: 3 },
  { id: "2-2", level: 2 },
  { id: "3", level: 1 },
  { id: "3-1", level: 2 },
  { id: "3-1-1", level: 3 },
  { id: "4", level: 1 },
  { id: "4-1", level: 2 },
  { id: "5", level: 1 },
  { id: "5-1", level: 2 },
  { id: "5-2", level: 2 },
  { id: "5-2-1", level: 3 },
  { id: "5-2-2", level: 3 },
  { id: "5-2-2-1", level: 4 },
  { id: "5-2-2-1-1", level: 5 },
  { id: "5-3", level: 2 },
  { id: "6", level: 1 },
  { id: "7", level: 1 },
  { id: "7-1", level: 2 }
];

var convert = nodes => {
  const stack = [];
  const result = [];
  let current = result;

  let depth = 1;

  nodes.forEach(node => {
    if (node.level === depth) {
      // sibling
      current.push({ ...node });
    } else if (depth < node.level) {
      // child
      depth++;
      current[current.length - 1].child = [{ ...node }];
      stack.push(current);

      current = current[current.length - 1].child;
    } else {
      // parent
      let loop = depth - node.level;
      while (loop--) {
        current = stack.pop();
        depth--;
      }

      current.push({ ...node });
    }
  });

  return result;
};

console.log(JSON.stringify(convert(resData), null, 2));

tree2.js

// link: stackoverflow.com/a/18018037/3793078
const data = [
  { id: 1, text: "1", parent: 0 },
  { id: 5, text: "2", parent: 0 },
  { id: 9, text: "3", parent: 0 },
  { id: 10, text: "4", parent: 0 },
  { id: 11, text: "5", parent: 0 },
  { id: 12, text: "6", parent: 0 },
  { id: 2, text: "1-1", parent: 1 },
  { id: 4, text: "1-2", parent: 1 },
  { id: 13, text: "1-3", parent: 1 },
  { id: 3, text: "1-1-1", parent: 2 },
  { id: 6, text: "2-1", parent: 5 },
  { id: 7, text: "2-2", parent: 5 },
  { id: 8, text: "2-1-1", parent: 6 }
];

function list_to_tree(list) {
  var map = {};

  for (let i = 0; i < list.length; i += 1) {
    map[list[i].id] = i; // initialize the map
    list[i].children = []; // initialize the children
  }

  let node, roots = [];
  for (let i = 0; i < list.length; i += 1) {
    node = list[i];
    if (node.parent !== 0) {
      // if you have dangling branches check that map[node.parentId] exists
      list[map[node.parent]].children.push(node);
    } else {
      roots.push(node);
    }
  }
  return roots;
}

console.log(data);
console.log("-----------");
console.log(JSON.stringify(list_to_tree(data), null, 2));

tree1.js result:

[{
  "id": "1",
  "level": 1
}, {
  "id": "2",
  "level": 1,
  "child": [{
    "id": "2-1",
    "level": 2,
    "child": [{
      "id": "2-1-1",
      "level": 3
    }]
  }, {
    "id": "2-2",
    "level": 2
  }]
}, {
  "id": "3",
  "level": 1,
  "child": [{
    "id": "3-1",
    "level": 2,
    "child": [{
      "id": "3-1-1",
      "level": 3
    }]
  }]
}, {
  "id": "4",
  "level": 1,
  "child": [{
    "id": "4-1",
    "level": 2
  }]
}, {
  "id": "5",
  "level": 1,
  "child": [{
    "id": "5-1",
    "level": 2
  }, {
    "id": "5-2",
    "level": 2,
    "child": [{
      "id": "5-2-1",
      "level": 3
    }, {
      "id": "5-2-2",
      "level": 3,
      "child": [{
        "id": "5-2-2-1",
        "level": 4,
        "child": [{
            "id": "5-2-2-1-1",
            "level": 5
          }]
      }]
    }]
  }, {
    "id": "5-3",
    "level": 2
  }]
}, {
  "id": "6",
  "level": 1
}, {
  "id": "7",
  "level": 1,
  "child": [{
    "id": "7-1",
    "level": 2
  }]
}]