check-constraints

Parsing PostgreSQL CHECK constraints into an AST.

npm run test

What?

This plugin pulls all of the CHECK constraints from postgres and transforms them into constraint directives on the relevant input fields.

For example, given a table defined like this:

CREATE TABLE users (
  id SERIAL PRIMARY KEY,
  email TEXT CHECK (email ~* '^.+@.+\..+$'),
  age INT CHECK (age >= 18),
  username TEXT CHECK (length(username) > 0),
  bio TEXT CHECK (length(bio) <= 500)
);

The following input object would be generated:

input UserInput {
  email: Email! @constraint(pattern: "^.+@.+\\..+$")
  age: Int @constraint(min: 18)
  username: String! @constraint(minLength: 1)
  bio: String @constraint(maxLength: 500)
}

To bring this (somewhat crazy idea) to it's logical conclusion, you could then run this through a codegen tool such as graphql-codegen-typescript-validation-schema to generate validation schemas for your frontend forms.

import * as v from 'valibot'

export function UserInputSchema(): v.GenericSchema<UserInput> {
  return v.object({
    email: v.pipe(v.pipe(v.string(), v.email()), v.regex(/^.+@.+\..+$/), v.minLength(1), v.maxLength(99)),
    age: v.pipe(v.number(), v.minValue(18)),
    bio: v.nullish(v.pipe(v.string(), v.maxLength(500))),
    username: v.pipe(v.string(), v.minLength(1)),
  })
}

Installation

npm install --save check-constraints

import {
  makeConstraintDirectivePlugin,
  ConstraintDirectiveTypeDefsPlugin,
} from "check-constraints";

const preset: GraphileConfig.Preset = {
  // ...

  plugins: [
    makeConstraintDirectivePlugin({
      // Optional: include constraint directives in field descriptions
      // This makes constraints visible in GraphiQL and other GraphQL explorers
      printConstraintInDescription: false, // default
    }),
    ConstraintDirectiveTypeDefsPlugin,
  ],

  // ...
};

Or use the default configuration:

import {
  ConstraintDirectivePlugin,
  ConstraintDirectiveTypeDefsPlugin,
} from "check-constraints";

const preset: GraphileConfig.Preset = {
  // ...

  plugins: [
    ConstraintDirectivePlugin, // Same as makeConstraintDirectivePlugin()
    ConstraintDirectiveTypeDefsPlugin,
  ],

  // ...
};

Packaging

npm run build
# Optionally test locally
npm pack
# Publish
npm publish