kysely-hydrate

library0.10.2jsnpmunverified

A TypeScript library extending Kysely with utilities for hydrating SQL query results into rich, nested JavaScript objects. Current version 0.10.2, early release with frequent breaking changes. Unlike traditional ORMs that restrict SQL expressiveness, this library preserves full Kysely query capabilities while enabling nested joins, computed properties, mapped fields, and hydrated writes. Requires Node >=22.18.0 and Kysely ^0.28. Ships TypeScript definitions.

database

npm install kysely-hydrate

github ↗package ↗homepage ↗

INSTALL

IMPORT

SIG · KYSELY-HYDRATE

kysely-hydrate

databasejavascriptv0.10.2

harness data pending

Install & Compatibility

Where this runs

No compatibility data collected yet for this library.

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

querySet

✓ import { querySet } from 'kysely-hydrate'

✗ import { QuerySet } from 'kysely-hydrate'

Function is lowercased; named export, not default.

attachOneOrThrow

✓ import { querySet } from 'kysely-hydrate' // attachOneOrThrow is a method on QuerySet

✗ import { attachOneOrThrow } from 'kysely-hydrate'

attachOneOrThrow is not a named export; it's a method on a QuerySet instance.

leftJoinMany

✓ import { querySet } from 'kysely-hydrate' // used as querySet(db).leftJoinMany(...)

✗ import { leftJoinMany } from 'kysely-hydrate'

leftJoinMany is a method on QuerySet, not a standalone function.

Demonstrates hydrating a user-post one-to-many join into nested objects using Kysely Hydrate.

import { querySet } from 'kysely-hydrate'; import { Kysely, PostgresDialect } from 'kysely'; import pg from 'pg'; const db = new Kysely<{ user: { id: number; name: string }; post: { id: number; title: string; userId: number } }>({ dialect: new PostgresDialect({ pool: new pg.Pool({ connectionString: process.env.DATABASE_URL ?? '' }) }) }); async function main() { const users = await querySet(db) .selectAs('user', db.selectFrom('user').select(['id', 'name'])) .leftJoinMany('posts', querySet(db).selectAs('posts', db.selectFrom('post').select(['id', 'title', 'userId'])), 'posts.userId', 'user.id' ) .execute(); console.log('Hydrated users:', JSON.stringify(users, null, 2)); } main().catch(console.error);

Debug

Known issues

breakingLibrary is in early release; expect breaking changes in minor and patch versions before 1.0.

fix

Pin to exact version and review changelogs before upgrading.

affects: <1.0

gotchaMethods like attachOneOrThrow and leftJoinMany are only available on QuerySet instances, not directly imported.

fix

Always import 'querySet' and chain methods.

affects: >=0.1

gotcharequires Node >=22.18.0; older Node versions will throw import errors.

fix

Use Node 22.18.0 or later, or use a transpiler like esbuild.

affects: >=0.10

breakingKysely peer dependency is ^0.28; incompatible with Kysely 0.27 or 0.29.

fix

Ensure project uses Kysely 0.28.x.

affects: >=0.10

deprecatedNo deprecated features documented yet; API is unstable.

fix

Keep up with GitHub releases for migration guides.

affects: >=0.1

Errors

Common errors & fixes

TypeError: querySet(...).selectAs is not a function

Incorrect import or library not installed properly; or using old version without selectAs.

fix

Ensure kysely-hydrate is installed (npm i kysely-hydrate) and import 'querySet' correctly. Check version >=0.1.

Module not found: Error: Can't resolve 'kysely-hydrate'

Package not installed or missing from package.json.

fix

Run npm install kysely-hydrate

Error: Cannot find module 'kysely' (or 'kysely' peer dependency not met)

Kysely is a peer dependency and not installed.

fix

Install kysely: npm install kysely@^0.28

Upgrade

Version history

0.10.2latest on npm

Audit

Dependencies

kyselyrequiredPeer dependency: core query builder that kysely-hydrate extends

Agent activity

2 hits · last 30 days

node

Resources

githubhttps://github.com/GiacoCorsiglia/kysely-hydrate ↗

packagekysely-hydrate ↗

homepagehttps://github.com/GiacoCorsiglia/kysely-hydrate#readme ↗