⚙️ Gearpipe

Gearpipe is a TS/JS utility that allows you to write sync and async functional pipelines in a very readable manner, similar to the ES Pipeline Operator Proposal.

Install gearpipe from npm

Features

• Tiny (403B), universal build, no dependencies.
• Async or sync pipelines with correct type inference. Even if pipeline is async, type inference considers it as sync for better DX.
• Composable and lazy-executing.
• Pairs well with sync/async toolbelts like lodash, rambda, modern-async, etc.

Async example

With the .async() method, gearpipe infers the types of each step as if they were synchronous.

Let's fetch a hypothetical user api with limited concurrency, then sort the results with lodash.

import { gearpipe } from 'gearpipe'
import { mapLimit } from 'modern-async'
import { sortBy } from 'lodash'

type User = {
  age: number
}

async function getUser(id: string): Promise<User> {
  return await fetch(`/users/${id}/`).then((resp) => resp.json())
}

async function getUsersByAge(ids: string[]): Promise<User[]> {
  return await gearpipe(ids)
    // async step
    .do((/** string[] */ ids) => mapLimit(ids, getUser, 3))>
    // sync step
    .do((/** User[] */ users) => sortBy(users, (x) => x.age))
    .async()
}

Notice that the sortBy step receives an awaited users variable. The two pipeline steps, one async and one sync, both read synchronously.

Sync example

With the .sync() method, gearpipe acts a lot like other pipeline utilities like lodash's _.chain()

import { gearpipe } from 'gearpipe'

function uselesslyComplexOperation(nums: number[]) {
  return gearpipe(nums)
    .do((/** number[] */ nums) => nums.map((x) => x * 2).join(','))
    .do((/** string */ str) => str.split(',').map((x) => parseInt(x) * 2))
    .sync()
}

uselesslyComplexOperation([1, 2, 3]) //=> [4, 8, 12]