Flatten javascript objects into a single-depth object with ES6

README.md

Flatten a deep javascript object into single-depth object with ES6

Call it via:

const flat = flatten( realDeepObject ),
      flatDotted = flatten( realDeepObject, '', '.' );

Test case:

const realDeepObject = {
  level1: {
    level2: {
      level3: {
        more: 'stuff', //duplicate key
        other: 'stuff',
        level4: {
          the: 'end',
        },
      },
    },
    level2still: {
      last: 'one',
    },
    am: 'bored',
  },
  more: 'stuff', //duplicate key
  ipsum: {
    lorem: 'latin',
  },
};

const flat = flatten( realDeepObject ),
      flatDotted = flatten( realDeepObject, '', '.' );

console.log( flat, flatDotted );

Output:

{ '/level1/level2/level3/more': 'stuff',
  '/level1/level2/level3/other': 'stuff',
  '/level1/level2/level3/level4/the': 'end',
  '/level1/level2still/last': 'one',
  '/level1/am': 'bored',
  '/more': 'stuff',
  '/ipsum/lorem': 'latin' }

{ 'level1.level2.level3.more': 'stuff',
  'level1.level2.level3.other': 'stuff',
  'level1.level2.level3.level4.the': 'end',
  'level1.level2still.last': 'one',
  'level1.am': 'bored',
  'more': 'stuff',
  'ipsum.lorem': 'latin' }

flatten.js

/**
 * PRIVATE
 * Flatten a deep object into a one level object with it’s path as key
 *
 * @param  {object} object    - The object to be flattened
 * @param  {string} pathRoot  - Starts path with
 * @param  {string} pathDelim - The path delimeter
 * @return {object}           - The resulting flat object
 */
const flatten = (object, pathRoot = '/', pathDelim = '/') => {
  return Object.assign( {}, ...function _flatten( objectBit, path = '' ) {  //spread the result into our return object
    if (objectBit === null) {                                               //deal with null
      return { [path]: null }
    }
    path = path.length ? `${path}${pathDelim}` : pathRoot                   //deal with path
    return [].concat(                                                       //concat everything into one level
      ...Object.keys( objectBit ).map(                                      //iterate over object
        key => typeof objectBit[ key ] === 'object' ?                       //check if there is a nested object
          _flatten( objectBit[ key ], `${ path }${ key }` ) :               //call itself if there is
          ( { [ `${ path }${ key }` ]: objectBit[ key ] } )                 //append object with it’s path as key
      )
    )
  }( object ) )
};