Different return value of sync and async methods

[secult]

On Windows 7 I get the following behavior:
`

fsf=require('fs-filesystem')
let response = fsf.filesystemSync('C:')
console.log(response)
{ 'C:':
{ id: 'C:',
node: 'C:',
whole: true,
parent: 'C:',
name: 'C:',
size: 214748360704,
description: 'Local Fixed Disk',
protocol: null,
blockSize: null,
readOnly: null,
removable: false,
volumes: [ [Object] ] } }

fsf.default('C:',(err,response)=>{console.log(response)})
{ devices:
{ 'C:':
{ id: 'C:',
node: 'C:',
whole: true,
parent: 'C:',
name: 'C:',
size: 214748360704,
description: 'Local Fixed Disk',
protocol: null,
blockSize: null,
readOnly: null,
removable: false,
volumes: [Array] } } }
`

I would expect that I receive the same structure, e.g. filesystem async return value should be returned without the devices accommodating object (as shown in the documentation). Or perhaps it should be highlighted in the documentation that the return value object structure of filesystemSync is different based on the filter parameter (to not introduce breaking change to the library).