nu-schemats

library4.9.1jsnpmunverified

Schemats generates TypeScript interface definitions from PostgreSQL or MySQL database schemas. Version 4.9.1 is the latest stable release, with irregular release cadence. It supports generating types for all tables in a schema or specific tables, and provides both CLI and programmatic API. Key differentiators include config file support, type-safe query results integration with pg-promise, and handling of custom types.

database

npm install nu-schemats

github ↗package ↗homepage ↗

INSTALL

IMPORT

SIG · NU-SCHEMATS

nu-schemats

databasejavascriptv4.9.1

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.

schemats generate

✓ schemats generate -c postgres://user:pass@localhost/db -t users -o types.ts

✗ schemats generate -c postgres://user:pass@localhost/db -t users -o types.ts --type postgres

The database type is inferred from the connection string. Do not specify --type unless absolutely necessary.

generate

✓ import { generate } from 'schemats'; const config = { conn: 'postgres://...', table: ['users'] }; await generate(config);

✗ const schemats = require('schemats'); schemats.generate({...});

Schemats provides both ESM and CommonJS exports. The default export is the generate function, but named import is recommended for TypeScript.

schemats.json

✓ Place schemats.json in project root with config. Run 'schemats generate' without arguments.

✗ Using schemats.json with a different filename or path without --config option

Config file defaults to schemats.json in current working directory. Use --config to specify a different path.

Installs Schemats globally, generates TypeScript interfaces for a specific table, and imports them for type-safe database queries.

npm install -g schemats # Generate interfaces for table 'users' from PostgreSQL schemats generate -c postgres://postgres@localhost/mydb -t users -o types/users.ts // In your code: import * as users from './types/users'; async function getUsers(): Promise<users.users[]> { const db = await pgp('postgres://postgres@localhost/mydb'); return db.query('SELECT * FROM users'); }

Debug

Known issues

breakingSchemats v4.0.0 dropped support for Node.js < 10

fix

Upgrade Node.js to version 10 or later.

affects: >=4.0.0

breakingSchemats v3.0.0 changed the CLI interface: removed --type flag, connection string now implies database type

fix

Update CLI commands to not use --type. Connection string must include 'postgres://' or 'mysql://'.

affects: >=3.0.0 <3.0.0

gotchaSchemats generates interfaces for ALL tables in schema if -t is omitted, which may generate many unwanted files.

fix

Always specify -t <table> or use -s <schema> to limit scope.

affects: >=1.0.0

deprecatedSchemats v2.x allowed table parameter as a comma-separated list via CLI, which is now deprecated in favor of repeated -t flags.

fix

Use multiple -t flags instead: -t users -t posts

affects: >=1.0.0 <3.0.0

gotchaWhen using MySQL, schemats requires the mysql2 package (not mysql).

fix

Ensure mysql2 is installed: npm install mysql2

affects: >=1.0.0

gotchaGenerated interfaces use snake_case property names matching database columns, which may conflict with TypeScript naming conventions.

fix

Consider renaming properties manually or using a post-processing script.

affects: >=1.0.0

Errors

Common errors & fixes

Error: Cannot find module 'pg'

pg package not installed (required for PostgreSQL connections)

fix

npm install pg

schemats: error: connect ECONNREFUSED

Database server is not running or connection string is incorrect

fix

Verify database is running and connection string is correct: postgres://user:pass@host:port/db

TypeError: Cannot read property 'replace' of undefined

Missing or malformed connection string

fix

Provide a valid connection string: -c postgres://localhost/mydb

Warning: No tables found in schema public

Schema specified does not contain tables, or tables are in a different schema

fix

Use -s to specify the correct schema name

Upgrade

Version history

4.9.1latest on npm

Audit

Dependencies

pgrequiredRequired for PostgreSQL database connection

mysql2optionalRequired for MySQL database connection

pg-promiseoptionalCommonly used with Schemats for typed queries, but not a runtime dependency

Agent activity

5 hits · last 30 days

node

Resources

githubhttps://github.com/aldis-ameriks/schemats ↗

packagenu-schemats ↗

homepagehttps://github.com/aldis-ameriks/schemats#readme ↗