如何创建这个复杂的 Javascript 变量

// Will use named capturing groups to parse each line
const lineRegex = new RegExp(
  "^(?<tag>\\w+)" +        // Match and capture the tag in the beginning of the line (word characters)
  "_(?<record>\\d+)" +     // Match and capture the record (digits)
  "_(?<role>\\d+)" +       // Match and capture the role (digits)
  "_(?<individual>\\d+)" + // Match and capture the individual (digits)
  "\\s+" +                 // Match one or more whitespace characters
  "(?<value>.+)$"          // Match and capture the value (any characters until the end of the line)
);

function parse(input) {
  return input
    // get each line separately
    .split('\n')
    // parse it with a regex
    .map((line) => line.match(lineRegex).groups)
    // reduce the parsed lines to the required shape
    .reduce((agg, parsed) => {
      const out = {...agg};
      if (typeof out[parsed.record] === 'undefined') {
        // Make sure there is a record to append to
        out[parsed.record] = {};
      }
      if (typeof out[parsed.record][parsed.role] === 'undefined') {
        // Make sure there is a role in the record to append to
        out[parsed.record][parsed.role] = {};
      }
      if (typeof out[parsed.record][parsed.role][parsed.individual] === 'undefined') {
        // Make sure there is an individual to assign values to
        out[parsed.record][parsed.role][parsed.individual] = {};
      }
      
      // Store the actual value for the tag
      out[parsed.record][parsed.role][parsed.individual][parsed.tag] = parsed.value;
      return out;
    }, {});
}

const data = `name_1_2_1 Joseph Jones
name_1_2_2 Mary Poppins
name_1_2_3 Sebastian Quincy
age_1_2_1 20
age_1_2_2 40
age_1_2_3 60`;

console.log(parse(data));

const data = [
  `name_1_2_1 Joseph Jones`,
  `name_1_2_2 Mary Poppins`,
  `name_1_2_3 Sebastian Quincy`,
  `age_1_2_1 20`,
  `age_1_2_2 40`,
  `age_1_2_3 60`,
];

const keyedData = data.map(line => {
  const bits = line.split(" ");
  
  const route = bits.shift(); // name_1_2_1

  const keyBits = route.split("_"); // [name, 1, 2, 1]
  const key = keyBits.shift(); // name
  
  return {
    route: keyBits,
    key,
    val: bits.join(' ') // the left over `Joseph Jones`
  }
})


function buildObject(data){
  const finalObject = {}
  
  data.forEach(item => {
    // Reset the target for this item to the `root` object
    let target = finalObject;
    while(item.route.length){
      let routeFragment = item.route.shift();
      // If the target doesn't have a property on this key, create one
      if(!target.hasOwnProperty(routeFragment)){
        target[routeFragment] = {};
      }
      // Now set the new target 
      target = target[routeFragment];
    }
    // Finally, update that value.
    target[item.key] = item.val;
  })
  
  return finalObject
}

const result = buildObject(keyedData);
console.log(result);