js get object properties (incl inherited)

get-properties.js

const getMethods = (obj) => {
  let properties = new Set()
  let currentObj = obj

  do {
    Object.getOwnPropertyNames(currentObj).map(item => properties.add(item))
  } while ((currentObj = Object.getPrototypeOf(currentObj)))
  
  return [...properties.keys()].filter(item => typeof obj[item] === 'function')
}