object flatten and expand

flatten_and_expand.js

import _ from 'lodash';

const numberRE = /^(?:0|[1-9][0-9]*)$/;
const flatten = (originalData) => {
  const result = {};
  const stack = [];
  let paths = [];
  let data = JSON.parse(JSON.stringify(originalData));
  while(true) {
    data = { ...data };
    const key = Object.keys(data).shift();
    if (key) {
      const element = data[key];
      delete data[key];

      if (element !== null && typeof element === 'object' && Object.keys(element).length) {
        if (data) {
          stack.push([data, [...paths]]);
        }
        data = element;
        
        if (numberRE.test(key)) {
          if (paths.length && paths[paths.length - 1] === '.') {
            paths.pop();
          }
          paths.push(`[${key}]`);
        } else {
          paths.push(key);
        }
        paths.push('.');
      } else {
        result[`${paths.join('')}${key}`] = element;
      }
    }

    if (!Object.keys(data).length) {
      if (stack.length) {
        [data, paths] = stack.shift();
      } else {
        break;
      }
    }
  }
  
  return result;
}

const expand = (data) => {
  const keys = [];
  const values = [];
  const dataKeys = Object.keys(data);
  
  let key = dataKeys.shift();
  while(key) {
    keys.push(`result.${key}`);
    values.push(data[key]);
    key = dataKeys.shift();
  }

  const { result } = _.zipObjectDeep(keys, values);
  
  return result;
}