# new stuff dropped in duckkit 🦆

Zura Japoshvili — Thu, 21 May 2026 10:10:50 +0000

new stuff dropped in duckkit 🦆

typed event emitter. function composition. partial application.

here's what it looks like.

before

emitter.on('win', (amount) => {
  // amount is any 😬
})

emitter.emit('win', 'oops')  // no error
emitter.emit('wiiin', 500)   // typo. also no error.

after

const emitter = createEmitter<{
  win: number
  spin: void
  error: { code: number; message: string }
}>()

emitter.emit('win', 500)       // ✅
emitter.emit('win', 'oops')    // ❌ TypeScript error
emitter.emit('wiiin', 500)     // ❌ TypeScript error
emitter.emit('win')            // ❌ payload missing

define the map once. TypeScript does the rest.

pipeline — reusable composed functions

const process = pipeline(
  (s: string) => s.trim(),
  s => s.toUpperCase(),
  s => s.split(' '),
)

process('  hello world  ')  // ["HELLO", "WORLD"]
process('  foo bar  ')      // ["FOO", "BAR"]

async steps work too — mix sync and async freely.

curry

const multiply = curry((factor: number, value: number) => value * factor)

[1, 2, 3].map(multiply(2))   // [2, 4, 6]
[1, 2, 3].map(multiply(10))  // [10, 20, 30]

npm install duckkit

npm · GitHub

do you use typed emitters? or just wing it with strings? 👇

duckkit: the utils JS forgot, TypeScript needs, you keep rewriting🦆

Zura Japoshvili — Wed, 20 May 2026 10:22:41 +0000

duckkit: the utils JS forgot, TypeScript needs, you keep rewriting 🦆

You know the trick. JSON.parse(JSON.stringify(obj)).

Works fine. Until you have a Date in there. Now it's a string. Congrats, you just silently broke something.

That's what pushed me to build duckkit — a TypeScript-first utility library with zero dependencies. Here are the things that don't exist anywhere else.

`delaySkippable` — a cancellable wait

This one came from game development. You want to wait 3 seconds before continuing, but skip immediately if the user clicks.

await delaySkippable(3000, () => userClickedSkip)

Resolves after 3 seconds normally. Resolves instantly if the condition becomes true. No timers to clear, no Promise races to write manually. Just works.

Also comes with:

await delayWithAbort(2000, abortController.signal)
await repeat(5, 500, i => animate(i))

`safe` — try/catch as a value

const result = safe(() => JSON.parse(raw))

if (result.ok) {
  console.log(result.value) // typed ✅
} else {
  console.log(result.error)
}

No try/catch blocks. No let data declared outside. Works with async too:

const result = await safeAsync(() => fetchUser(id))

`groupBy` that actually types its output

const grouped = groupBy(users, x => x.country)
// Record<"GE" | "US" | "DE", User[]> ✅

Full autocomplete on keys. TypeScript catches typos. The way it should work.

`topBy` — get the top N items by a field

const top5 = topBy(products, x => x.sales, 5)

You always end up writing .sort(...).slice(0, 5) and it's never clean. One line, typed.

`deepClone` that preserves `Date` objects

const clone = deepClone({ name: "Zura", createdAt: new Date() })
clone.createdAt // still a Date, not a string ✅

The JSON trick everyone uses silently converts Dates to strings. This doesn't.

`retry` and `parallel`

await retry(() => fetchUser(id), 3, 1000)
await parallel([fetchA, fetchB, fetchC], { concurrency: 2 })

`partition` with proper types

const [admins, rest] = partition(users, x => x.isAdmin)
// both arrays are User[] ✅

Everything is tree-shakeable

import { groupBy, partition } from 'duckkit/array'
import { safe, retry } from 'duckkit/async'
import { delaySkippable, repeat } from 'duckkit/delay'
import { formatDate, timeAgo } from 'duckkit/date'

Only what you import ends up in the bundle. Zero dependencies. ESM + CJS. Full TypeScript declarations.

Install

npm install duckkit

npm · GitHub · Docs

Still early (v0.1.3) but everything is tested and typed. What helper do you always end up writing from scratch? I might be missing it. 👇

DEV Community: Zura Japoshvili