how to simplify a function which performs manipulation of datas?

Question

We have created a function that will convert the data into the desired format, but it has a lot of code and is difficult to understand.

below is the code for it

const data = [{"id":"Client 1","advisorName":"Dhanush","managerName":"Nikolai","clientName":"Thor Odin","goalName":"","goalAmount":"","goals":2,"score":0.855,"lastModified":"22/1/2022","equityFixedIncome":"","subRows":[{"id":"goal-1","clientName":"","managerName":"","advisorName":"","goalName":"Retirement1","goalAmount":10000,"goals":1,"equityFixedIncome":"60/40","lastModified":"22/1/2022","score":0.99},{"id":"goal-2","clientName":"","managerName":"","advisorName":"","goalName":"Save For Child Education","goalAmount":70000,"goals":1,"equityFixedIncome":"55/45","lastModified":"5/12/2023","score":0.72}]},{"id":"Client 2","advisorName":"Dhanush","managerName":"Nikolai","clientName":"Steve Rogers","goalName":"Save for Investment","goalAmount":67000,"goals":1,"score":0.7,"lastModified":"22/1/2022","equityFixedIncome":"60/40"},{"id":"Client 3","advisorName":"Dhanush","managerName":"Nikolai","clientName":"Wanda Vision","goals":0,"score":0.9,"lastModified":"","equityFixedIncome":""},{"id":"Client 4","advisorName":"Dhanush","managerName":"Nikolai","clientName":"Tony Stark","goalName":"","goalAmount":"","goals":2,"score":0.29,"lastModified":"27/10/2019","equityFixedIncome":"","subRows":[{"id":"goal-4","clientName":"","managerName":"","advisorName":"","goalName":"Education Loan","goalAmount":500,"goals":1,"equityFixedIncome":"60/40","lastModified":"27/10/2019","score":0.29},{"id":"goal-5","clientName":"","managerName":"","advisorName":"","goalName":"House Loan","goalAmount":23000,"goals":1,"equityFixedIncome":"30/70","lastModified":"16/6/2022","score":0.29}]},{"id":"Client 5","advisorName":"Joe","managerName":"Nikolai","clientName":"Hack Eye","goalName":"Save For World Tour","goalAmount":400000,"goals":1,"score":0.74,"lastModified":"","equityFixedIncome":"60/40"},{"id":"Client 6","advisorName":"Joe","managerName":"Nikolai","clientName":"Nick Fury","goalName":"","goalAmount":"","goals":2,"score":0.44499999999999995,"lastModified":"9/3/2022","equityFixedIncome":"","subRows":[{"id":"goal-7","clientName":"","managerName":"","advisorName":"","goalName":"To Build A Workspace","goalAmount":42340,"goals":1,"equityFixedIncome":"60/40","lastModified":"9/3/2022","score":0.6},{"id":"goal-8","clientName":"","managerName":"","advisorName":"","goalName":"Cloud Examination","goalAmount":8730,"goals":1,"equityFixedIncome":"30/70","lastModified":"9/11/2021","score":0.29}]},{"id":"Client 7","advisorName":"Joe","managerName":"Nikolai","clientName":"Star Lord","goalName":"Save For Child Education","goalAmount":400000,"goals":1,"score":0.93,"lastModified":"","equityFixedIncome":"55/45"},{"id":"Client 8","advisorName":"Pal","managerName":"Rohan","clientName":"Thanos","goalName":"","goalAmount":"","goals":3,"score":0.29,"lastModified":"2/11/2019","equityFixedIncome":"","subRows":[{"id":"goal-10","clientName":"","managerName":"","advisorName":"","goalName":"Relocation Expense Goal","goalAmount":400000,"goals":1,"equityFixedIncome":"22/78","lastModified":"2/11/2019","score":0.29},{"id":"goal-11","clientName":"","managerName":"","advisorName":"","goalName":"Save for to buy bike","goalAmount":400000,"goals":1,"equityFixedIncome":"50/50","lastModified":"1/1/2020","score":0.29},{"id":"goal-12","clientName":"","managerName":"","advisorName":"","goalName":"Save For Education","goalAmount":400000,"goals":1,"equityFixedIncome":"65/35","lastModified":"9/5/2022","score":0.29}]},{"id":"Client 9","advisorName":"Pal","managerName":"Rohan","clientName":"Ego","goalName":"Save For Education","goalAmount":400000,"goals":1,"score":0.72,"lastModified":"","equityFixedIncome":"65/35"},{"id":"Client 10","advisorName":"Pal","managerName":"Rohan","clientName":"Bruce Banner","goalName":"","goalAmount":"","goals":2,"score":0.975,"lastModified":"9/10/2018","equityFixedIncome":"","subRows":[{"id":"goal-14","clientName":"","managerName":"","advisorName":"","goalName":"Car Loan","goalAmount":23000,"goals":1,"equityFixedIncome":"60/40","lastModified":"9/10/2018","score":0.99},{"id":"goal-15","clientName":"","managerName":"","advisorName":"","goalName":"Bike Loan","goalAmount":4600,"goals":1,"equityFixedIncome":"30/70","lastModified":"9/11/2021","score":0.96}]}]

function firstLevelManagerGroup(data){
  return data.reduce(
    (acc, row) => {
      if (row.advisorName !== acc.level1.clientName) {
        let newRow1 = {
          advisorName: row.advisorName,
          managerName: row.managerName,
          id: "",
          clientName: "",
          goalName: "",
          goalAmount: "",
          goals: "",
          score: "",
          lastModified: "",
          equityFixedIncome: "",
          subRows: [],
        };
        acc.result.push(newRow1);
        acc.level1.clientName = row.advisorName;
        acc.level1.arr = newRow1.subRows;
      }
      let newRow2 = {
        advisorName: "",
        managerName: "",
        id: row.id,
        clientName: row.clientName,
        goalName: row.goalName,
        goalAmount: row.goalAmount,
        goals: row.goals,
        score: row.score,
        lastModified: row.lastModified,
        equityFixedIncome: row.equityFixedIncome,
      };
  
      if(row.subRows) {
        acc.level2.arr = newRow2.subRows = [];
      }
      acc.level1.arr.push(newRow2);
  
      if (row.subRows) {
        row.subRows.forEach((subRow) => {
          acc.level2.arr.push({ ...subRow });
        });
      }
      return acc;
    },
    {
      result: [],
      level1: { clientName: "", arr: null },
      level2: { arr: null },
    }
  ).result;
}



const groupManager = (data, keyName) => {
  let val = firstLevelManagerGroup(data)
  const emptyNode = {
    managerName: "",
    advisorName: "",
    id: "",
    clientName: "",
    goalName: "",
    goalAmount: "",
    goals: "",
    score: "",
    lastModified: "",
    equityFixedIncome: "",
    subRows: [],
  };
  
  const groups = val.reduce((acc, item) => {
    acc[item[keyName]] ??= [];
    acc[item[keyName]].push({ ...item, [keyName]: "" });
    return acc;
  }, {});

  return Object.entries(groups)
    .map(([keyValue, subRows]) => (
        { ...emptyNode,  [keyName]: keyValue , subRows }
    ));  
};

console.log(JSON.stringify(groupManager(data, 'managerName')));

And why I am doing this is because, I am creating a multi level nested expandable table which requires this kind of structure. You can get the working demo link here - https://codesandbox.io/s/tanstack-table-expansion-1t77ks?file=/src/styles.css

Could you please let me know the possible solution to create a better function for it?