flatten.js

// flattenObject recursively takes an object with an arbitrary depth 
// and return an object with all properties grouped at the root level.
// Useful to have reduce digitalData to the same level
// Exemple:
// const nestedObject = { a: { b: 1}, c: { d: { e: 3 }}}, f: [1,2,{ g: "lol"}]}
// flattenObject(nestedObject, null, {})
// { b: 1, e: 3, f: [1,2], g: "lol"}
function flattenObject(object, key, output) {
  // It's an object ? Recrusive call
  if (typeof object == "object" && !(object instanceof Array)) {
    Object.keys(object).forEach(property => flattenObject(object[property], property, output));
    // An array ? Recursive call !
  } else if (object instanceof Array) {
    object.forEach(value => flattenObject(value, key, output));
    // a primitive - (we don't handle Set, Map, ...) for now
  } else {
    if (output[key] != undefined) {
      if (output[key] instanceof Array) {
        output[key].push(object);
      } else {
        var temp = [];
        temp.push(output[key]);
        temp.push(object);
        output[key] = temp;
      }
    } else {
      output[key] = object;
    }
    return output;
  }
  return output;
}