function sequentialCallback (...fns) {
return (...args) => {
const done = args.pop()
const next = (error, ...args) => {
if (error) return done(error)
if (fns.length) {
const fn = fns.shift()
return fn(...args, next)
}
return done(null, ...args)
}
return next(null, ...args)
}
}