TypeORM many to many lazy relation jointable custom table name TypeGraphQL Example (with bi-directional conect GraphQL Approach)

author.entity.ts

import { Entity, PrimaryGeneratedColumn, Column, BaseEntity, ManyToMany } from 'typeorm';
import { ObjectType, Field, ID, InputType, ArgsType, Int } from 'type-graphql';
import { Book } from '../book/book.entity';

@Entity()
@ObjectType()
export class Author extends BaseEntity {

    @PrimaryGeneratedColumn("uuid")
    @Field(type => ID)
    id: string;

    @Column()
    @Field()
    title: string

    @Column({ unique: true })
    @Field()
    slug: string

    @Column()
    @Field()
    description: string

    @Column()
    @Field()
    image: string

    @Column()
    @Field()
    birth: string

    @Column()
    @Field()
    death: string

    @Column()
    @Field()
    translator: boolean

    // book_authors
    @ManyToMany(type => Book, book => book.authors, { lazy: true })
    @Field(type => [Book])
    books: Promise<Book[]>
}

@InputType()
export class AuthorInput {

    @Field(type => ID)
    id: string;


    @Field()
    title: string

    @Field()
    slug: string

    @Field()
    description: string


    @Field()
    image: string

    @Field()
    birth: string

    @Field()
    death: string

    @Field()
    translator: boolean
}

@InputType()
export class CreateAuthorInput {

    @Field()
    title: string

    @Field()
    slug: string

    @Field()
    description: string

    @Field()
    image: string

    @Field()
    birth: string

    @Field()
    death: string

    @Field()
    translator: boolean
}

@ArgsType()
export class AuthorsFilter {
    @Field({ nullable: true })
    title?: string;

    @Field(type => Int, { nullable: true })
    skip?: number;

    @Field(type => Int, { nullable: true })
    take?: number;
}

@ArgsType()
export class AuthorFilter {
    @Field({ nullable: true })
    id?: string;

    @Field({ nullable: true })
    title?: string;

    @Field({ nullable: true })
    slug?: string;
}

author.resolver.ts

import { Resolver, Query, Args, Arg, Mutation, Authorized } from "type-graphql";
import { Author, AuthorsFilter, AuthorFilter, CreateAuthorInput } from './author.entity';
import { Like, getRepository } from 'typeorm';
import { GraphQLUpload } from 'graphql-upload';
import { createWriteStream } from 'fs';
import { Upload } from '../../types/Upload';
import * as path from 'path';

@Resolver(Author)
export class AuthorResolver {

    @Query(returns => [Author])
    async allAuthors(
        @Args() { title, skip, take }: AuthorsFilter
    ): Promise<Author[]> {
        if (title) {
            return Author.find({ where: { title: Like(`${title}%`), skip, take } })
        }
        return Author.find({ skip, take });
    }

    @Query(returns => Author)
    async author(
        @Args() { id, title, slug }: AuthorFilter
    ): Promise<Author> {
        if (id) {
            return Author.findOne(id)
        }
        if (title) {
            return Author.findOne(title)
        }
        if (slug) {
            return Author.findOne(slug)
        }
        throw new Error('book not found');
    };

    @Mutation(returns => Author)
    async createAuthor(
        @Arg('author') input: CreateAuthorInput
    ): Promise<CreateAuthorInput> {
        const author = new Author();
        author.title = input.title;
        author.slug = input.slug;
        author.description = input.description;
        author.image = input.image;
        author.birth = input.birth;
        author.death = input.death;
        author.translator = input.translator;
        await author.save();
        return author;
    }

    @Mutation(returns => Author)
    async updateAuthor(
        @Arg('id') id: string,
        @Arg('author') input: CreateAuthorInput
    ): Promise<CreateAuthorInput> {
        const authorRepository = getRepository(Author);
        const author = await authorRepository.findOne(id);
        if (!author) {
            throw new Error('author not found');
        }
        author.title = input.title;
        author.slug = input.slug;
        author.description = input.description;
        author.image = input.image;
        author.birth = input.birth;
        author.death = input.death;
        author.translator = input.translator;
        await authorRepository.save(author);
        return author;
    }

    @Authorized("ADMIN")
    @Mutation(returns => Author)
    async deleteAuthor(
        @Arg('id') id: string
    ): Promise<Author> {
        const authorRepository = getRepository(Author);
        const author = await authorRepository.findOne(id);
        if (!author) {
            throw new Error('author not found!');
        }
        await authorRepository.delete(id);
        return author;
    }

    @Mutation(returns => Boolean)
    async createAuthorImage(@Arg('file', () => GraphQLUpload) file: Upload) {
        const { filename, mimetype, createReadStream } = await file;
        const acceptedTypes = ['image/jpeg', 'image/png'];
        if (acceptedTypes.indexOf(mimetype) !== -1) {
            const stream = createReadStream();
            stream.pipe(createWriteStream(path.join(__dirname, `../../../images/authors/${filename}`)));
            return true;
        }
        throw new Error('Unsupported image type.')
    };
}

// postman operations
// {"query":"mutation CreateAuthorImage($file: Upload!) {\n  createAuthorImage(file: $file)\n}\n"}

book.entity.ts

import { Entity, PrimaryGeneratedColumn, Column, BaseEntity, ManyToOne, ManyToMany, JoinTable} from 'typeorm';
import { ObjectType, Field, ID, Int, ArgsType, InputType } from 'type-graphql';
import { Publisher } from '../publisher/publisher.entity';
import { Author } from '../author/author.entity';

@Entity()
@ObjectType()
export class Book extends BaseEntity {
    @PrimaryGeneratedColumn("uuid")
    @Field(type => ID)
    id: string;

    @Column()
    @Field()
    title: string;

    @Column({ unique: true })
    @Field()
    slug: string;

    @Column()
    @Field()
    image: string;

    @Column()
    @Field()
    description: string;

    @Column()
    @Field()
    firstEditionYear: string;

    @Column()
    @Field()
    edition: string;

    @Column()
    @Field()
    numberOfPage: string;

    @Column()
    @Field()
    isbn: string;

    @Column()
    @Field()
    language: string;

    @Column()
    publisherId: string;

    @ManyToOne(type => Publisher, { lazy: true })
    @Field(type => Publisher)
    publisher: Promise<Publisher>;

    // book_authors
    @ManyToMany(type => Author, author => author.books, { lazy: true })
    @JoinTable({
        name: "book_author", // table name for the junction table of this relation
        joinColumn: {
            name: "bookId",
            referencedColumnName: "id"
        },
        inverseJoinColumn: {
            name: "authorId",
            referencedColumnName: "id"
        }
    })
    @Field(type => [Author])
    authors: Promise<Author[]>;
}

@InputType()
export class CreateBookInput {

    @Field()
    title: string;

    @Field()
    slug: string;

    @Field()
    image: string;

    @Field()
    description: string;

    @Field()
    firstEditionYear: string;

    @Field()
    edition: string;

    @Field()
    numberOfPage: string;

    @Field()
    isbn: string;

    @Field()
    language: string;

    @Field()
    publisherId: string;
}
@ArgsType()
export class BooksFilter {
    @Field({ nullable: true })
    title?: string;

    @Field(type => Int, { nullable: true })
    skip?: number;

    @Field(type => Int, { nullable: true })
    take?: number;
}

@ArgsType()
export class BookFilter {
    @Field({ nullable: true })
    id?: string;

    @Field({ nullable: true })
    title?: string;

    @Field({ nullable: true })
    slug?: string;
}

book.resolver.ts

import { Resolver, Query, Args, Arg, Mutation, Authorized } from "type-graphql";
import { Book, BookFilter, BooksFilter, CreateBookInput } from './book.entity';
import { Like, getRepository } from 'typeorm';
import { GraphQLUpload } from 'graphql-upload';
import { createWriteStream } from 'fs';
import { Upload } from '../../types/Upload';
import * as path from 'path';
import { Author, AuthorInput } from '../author/author.entity';

@Resolver(Book)
export class BookResolver {

    @Query(returns => [Book])
    async allBooks(
        @Args() { title, skip, take }: BooksFilter
    ): Promise<Book[]> {
        if (title) {
            return Book.find({ where: { title: Like(`${title}%`) }, skip, take });
        }
        return Book.find({ skip, take });
    }

    @Query(returns => Book)
    async book(
        @Args() { id, title, slug }: BookFilter
    ): Promise<Book> {
        if (id) {
            return Book.findOne(id)
        }
        if (title) {
            return Book.findOne(title)
        }
        if (slug) {
            return Book.findOne(slug)
        }
        throw new Error('book not found');
    };

    @Mutation(returns => Book)
    async createBook(
        @Arg('book') input: CreateBookInput,
        @Arg('authors', type => [AuthorInput]) authors: Author[]
    ): Promise<CreateBookInput> {
        const book = new Book();
        book.title = input.title;
        book.slug = input.slug;
        book.image = input.image;
        book.description = input.description;
        book.firstEditionYear = input.firstEditionYear;
        book.edition = input.numberOfPage;
        book.numberOfPage = input.numberOfPage;
        book.isbn = input.isbn;
        book.language = input.language;
        book.publisherId = input.publisherId;
        book.authors = Promise.resolve(authors);
        await book.save();
        return book;
    }

    @Mutation(returns => Book)
    async updateBook(
        @Arg('id') id: string,
        @Arg('book') input: CreateBookInput
    ): Promise<CreateBookInput> {
        const bookRepository = getRepository(Book);
        const book = await bookRepository.findOne(id);
        if (!book) {
            throw new Error('book not found');
        }
        book.title = input.title;
        book.slug = input.slug;
        book.image = input.image;
        book.description = input.description;
        book.firstEditionYear = input.firstEditionYear;
        book.edition = input.edition;
        book.numberOfPage = input.numberOfPage;
        book.isbn = input.isbn;
        book.language = input.language;
        book.publisherId = input.publisherId;
        await bookRepository.save(book);
        return book;
    }

    @Authorized("ADMIN")
    @Mutation(returns => Book)
    async deleteBook(
        @Arg('id') id: string
    ): Promise<Book> {
        const bookRepository = getRepository(Book);
        const book = await bookRepository.findOne(id);
        if (!book) {
            throw new Error('book not found!')
        }
        await bookRepository.delete({ id });
        return book;
    }

    @Mutation(returns => Boolean)
    async createBookImage(@Arg('file', () => GraphQLUpload) file: Upload) {
        const { filename, mimetype, createReadStream } = await file;
        const acceptedTypes = ['image/jpeg', 'image/png'];
        if (acceptedTypes.indexOf(mimetype) !== -1) {
            const stream = createReadStream();
            stream.pipe(createWriteStream(path.join(__dirname, `../../../images/books/${filename}`)));
            return true;
        }
        throw new Error('Unsupported image type.')
    };
}

// postman operations
// {"query":"mutation CreateBookImage($file: Upload!) {\n  createBookImage(file: $file)\n}\n"}

Very helpful!! Thanks!!

BTW, I saw a mix of Book.findOne and bookRepository.findOne. What's the difference?

Thanks!!! As adsee42 said "Very helpful!!" !! :)