getMethods js function

getMethods.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')
    };