sequential

• sequential

The sequential function is typically used when multiple asynchronous operations need to be executed in sequence. It takes an array of functions functions that return a Promise and executes them serially. Each function can accept the result of the previous function wrapped in a PromiseSettledResult type as a parameter.

If an optional parameter initialValue is provided, it will be wrapped in a PromiseSettledResult of fulfilled status and passed to the first function. Otherwise, the first function will receive undefined as its parameter.

Added in v0.0.1

Usage

import { sequential } from 'parsnip-kit'

const functions = [
  async (arg?: PromiseSettledResult<number>) => {
    if (arg?.status === 'fulfilled') {
      return arg.value
    } else {
      throw new Error('test')
    }
  },
  async (arg?: PromiseSettledResult<number>) => {
    return arg?.status === 'fulfilled' ? arg.value + 1 : 0
  },
  async (arg?: PromiseSettledResult<number>) => {
    return arg?.status === 'fulfilled' ? arg.value * 2 : 0
  }
]
sequential(functions).then(res => { console.log(res) })
// [
//   { status: 'rejected', reason: new Error('test') },
//   { status: 'fulfilled', value: 0 },
//   { status: 'fulfilled', value: 0 }
// ]

sequential(functions, 0).then(res => { console.log(res) })
// [
//   { status: 'fulfilled', value: 1 },
//   { status: 'fulfilled', value: 2 },
//   { status: 'fulfilled', value: 4 }
// ]

API

Type Parameter

Arg	Type	Description
T		The value type returned by a function that returns a Promise

Arguments

Arg	Type	Optional	Default	Description
functions	((arg?: PromiseSettledResult<Awaited<T>>) => Promise<T>)[]	false	undefined	Array of functions that return Promise
initialValue	Awaited<T>	true	undefined	Initial Value

Returns

Type
Promise<PromiseSettledResult<Awaited<T>>[]>