Matt Wicks' answer to Sleep Number interview exercise

answer.js

/**
 * Given an array of Person objects, returns the root PersonTreeNode (the CEO).
 * @param {Person[]} employees - An array of Person objects representing all the employees of the company.
 * @returns {PersonTreeNode} The CEO of the organization.
 */
function generateTree(employees) {
  var ceo = null; 
  const employeeNodes = employees.map(emp => PersonTreeNode(emp));    
  const getNodeById = (id) => employeeNodes.filter(en => en.person.id === id)[0];

  employeeNodes.forEach(en => {    
    if (en.person.manager === null) {
      ceo = en;
    } else {
      const manager = getNodeById(en.person.manager.id);
      const directReporter = en;
      manager.directReports.push(directReporter);
    }
  });
 
  return ceo;
};