kysely

library0.29.2jsnpmunverified

Kysely is a type-safe and autocompletion-friendly TypeScript SQL query builder for Node.js, version 0.29.x (released Nov 2024). It provides a fluent API to build and execute SQL queries against PostgreSQL, MySQL, SQLite, and MSSQL databases with full TypeScript support. Unlike ORMs like TypeORM or Prisma, Kysely gives you direct control over SQL while preventing syntax errors and SQL injection at compile time. It is actively maintained with monthly releases.

database

npm install kysely

github ↗package ↗homepage ↗

INSTALL

IMPORT

SIG · KYSELY

kysely

databasejavascriptv0.29.2

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.

Kysely

✓ import { Kysely } from 'kysely'

✗ import Kysely from 'kysely'

Kysely uses named exports. Default export is not available.

PostgresDialect

✓ import { PostgresDialect } from 'kysely'

✗ import { PostgresDialect } from 'kysely/dialects'

Dialects are exported from the main package since v0.21.

sql

✓ import { sql } from 'kysely'

It's a helper for raw SQL expressions.

Initialize Kysely with PostgreSQL dialect, define a simple database schema, and execute a type-safe select query.

import { Kysely, PostgresDialect } from 'kysely' import { Pool } from 'pg' interface Person { id: number name: string age: number } interface Database { person: Person } const db = new Kysely<Database>({ dialect: new PostgresDialect({ pool: new Pool({ connectionString: process.env.DATABASE_URL }) }) }) async function main() { const person = await db .selectFrom('person') .select(['id', 'name']) .where('age', '>', 18) .executeTakeFirst() console.log(person) } main()

Debug

Known issues

breakingError: Cannot find module 'kysely' or its corresponding type declarations.

fix

Upgrade to v0.22+ or use 'kysely/dist/cjs' for CommonJS.

affects: <=0.21

gotchaType 'any' is not assignable to type 'never'.

fix

Define a proper database type interface for your tables.

affects: >=0.20

deprecatedMethod 'execute' is deprecated. Use 'executeTakeFirst' or 'executeTakeFirstOrThrow'.

fix

Replace .execute() with .executeTakeFirst() or .executeTakeFirstOrThrow() for single-row results.

affects: >=0.24

breakingconst db = new Kysely({ dialect: new SqliteDialect({ database: new Database('my.db') }) }) // TypeError: new Database is not a constructor

fix

Use synchronous SqliteDialect: new SqliteDialect({ database: new Database('my.db') }) or async callback for SQLite.

affects: >=0.24

gotchaProperty 'id' does not exist on type 'SelectExpression<DB, "person">'.

fix

Ensure your table type includes all columns you select. Use 'Selectable' wrapper from 'kysely' if needed.

affects: >=0.21

gotchaCannot query across tables without a join.

fix

Use .innerJoin() or .leftJoin() to join tables before selecting columns from them.

affects: >=0.20

gotchaKysely does not support automatic migrations like Prisma.

fix

Use a separate migration tool (e.g., 'kysely-codegen' or raw SQL files). Kysely is query-builder only.

affects: >=0.0

Errors

Common errors & fixes

Cannot find name 'Kysely'

Missing import or incorrect package install

fix

Install kysely: npm install kysely && import { Kysely } from 'kysely'

Type 'PostgresDialect' is not generic.

Using old import path or wrong version

fix

Upgrade to v0.21+ and import from 'kysely' directly.

Method 'executeTakeFirst' does not exist on type 'SelectQueryBuilder<...>'.

Using version <0.24 where executeTakeFirst was not introduced

fix

Upgrade to v0.24+ or use .execute() and handle arrays manually.

const pool = new Pool({ connectionString: process.env.DATABASE_URL }) // Pool is not defined

Missing pg package or import

fix

Install pg: npm install pg && import { Pool } from 'pg'

Error: The 'dialect' option is required.

Forgot to provide a dialect when creating Kysely instance

fix

Add dialect: new PostgresDialect({...}) (or other dialect) to the constructor.

Upgrade

Version history

0.29.2latest on npm

Audit

Dependencies

No dependency data recorded yet.

Agent activity

8 hits · last 30 days

node

Amazon

Resources

githubhttps://github.com/kysely-org/kysely ↗

packagekysely ↗

homepagehttps://kysely.dev ↗