megaera/dist/generate.test.js

GraphQL to TypeScript Generator

import { test, expect } from 'vitest';
import { buildSchema, typeFromAST } from 'graphql/utilities/index.js';
import { generateType } from './generate.js';
import { isObjectType } from 'graphql/type/index.js';
const schema = buildSchema(`
type User {
  name: String!
  birthday: Date!
  gender: Gender!
  favoriteBooks: [String]
}

type Object {
  name: String!
  age: Int
}

scalar Date

enum Gender {
  MALE
  FEMALE
}
`);
function getFieldType(name, fieldName) {
    const type = schema.getType(name);
    if (!isObjectType(type)) {
        throw new Error(`${name} is not object type.`);
    }
    const field = type.astNode?.fields?.find((f) => f.name.value === fieldName)?.type;
    if (!field) {
        throw new Error(`Cannot find ${fieldName} field in ${name}.`);
    }
    return typeFromAST(schema, field);
}
test('scalar type', () => {
    const birthdayType = getFieldType('User', 'birthday');
    const code = generateType(birthdayType);
    expect(code).toEqual('string');
});
test('enum type', () => {
    const code = generateType(schema.getType('Gender'));
    expect(code).toEqual(`'MALE' | 'FEMALE'`);
});
test('list type', () => {
    const favoriteBooksType = getFieldType('User', 'favoriteBooks');
    const code = generateType(favoriteBooksType);
    expect(code).toEqual('(string | null)[] | null');
});
test('object type', () => {
    const code = generateType(schema.getType('Object'));
    expect(code).toEqual('{name: string, age: number | null}');
});