Reduce an object filtering out some keys

const myObject = {a:1, b:2, c:3, d:4, e:5}

const reduced = ob => {
    const allowed = ['a', 'b']
    return Object.keys(ob)
      .filter(key => allowed.includes(key))
      .reduce((obj, key) => {
        obj[key] = ob[key]
        return obj
      }, {})
}

const reducedObject = reduced(myObject) // {a:1, b:2}