returns a path to the first leaf node in an query tree which passes a given predicate.

findPath.js

console.clear();

function findPath(node, predicate) {
  var depth = 0;
  var path = [];
  var found = false;
  function find(currentNode, i) {
    if (found) {
      return path;
    }
    path[depth] = i;
    // console.log('path: ' + path);
    if(isBranch(currentNode)) {
      // console.log('i: ' + i + '  depth '+ depth + '.  id: ' + currentNode.id);
      depth++;
      currentNode.children.forEach(find);
      depth--;
    }
    else {
      // console.log('i: ' + i + '  depth: ' + depth + '  id: ' + currentNode.id + '.  value: ' + currentNode.value);
     if (predicate(currentNode.value)) {
       found = true;
       return;
     }
    }
    return found ? path : undefined;
  }
  
  return find(node, 0);
}


// utils
function predicate(value) {
  console.log(value[0] === 'this');
  return value[0] === 'or';
}

function isBranch(node, operator) {
  return Array.isArray(node.children) &&
    !node.hasOwnProperty('value') &&
    !node.hasOwnProperty('field') &&
    (!operator || operator === node.operator);
}

//data

const query = {
  id: '1',
  operator: 'AND',
  children: [{
    id: '2',
    operator: 'AND',
    children: [
      {
        id: '3',
        opertator: 'OR',
        children: [
          {
            id: '4',
            field: 'BIO',
            operator: 'OR',
            value: ['omg', 'kanye'],
          },
          {
            id: '5',
            field: 'BIO',
            operator: 'OR',
            value: ['no', 'way'],
          }
        ]
      },
    ],
  }, {
    id: '6',
    operator: 'NOT',
    children: [
      {
        id: '7',
        field: 'BIO',
        operator: 'OR',
        value: ['this', 'that'],
      },
      {
        id: '8',
        field: 'BIO',
        operator: 'OR',
        value: ['or', 'the', 'other'],
      },
    ],
  }],
};

// execution

console.log('return this: ' + findPath(query, predicate));