toKeypath.js

const keypaths = [];
const values = [];

const mapper = (input, keypath = '') => {
  if (!_.isObject(input)) {
    keypaths.push(keypath);
    values.push(input);
  } else {
    
    const isArray = Array.isArray(input);
    
    if (keypath) {
      if (isArray) keypath += '[';
      else keypath += '.';
    };
    
    _.each(input, (val, key) => {
      const base = keypath + key + (isArray ? ']' : '');
    
      if (_.isObject(val)) {
        if (Array.isArray(val)) {
          val.forEach((v, i) => {
            mapper(v, `${base}[${i}]`);
          });
        } else {
          _.each(val, (v, k) => {
            mapper(v, `${base}.${k}`);
          });
        }
      } else {
        keypaths.push(base);
        values.push(val);
      }
    })
  }
};

mapper(obj);
return _.object(keypaths, values)