sequelize/index.js

var Sequelize = require('sequelize');
var sequelize = new Sequelize('test', '', '',
    {
        host: 'localhost',
        dialect: 'mysql',

        pool: {
            max: 5,
            min: 0,
            idle: 10000
        },
        //logging: false
    }
);

var Post = sequelize.define('post', {
    title: Sequelize.STRING,
    text:  Sequelize.TEXT,
},{
 getterMethods: {
    tagz() {
      return this.getTags().then(tagz => tagz.map(tag => tag.title))
    },
    age() {
        return (((new Date).getTime() - this.createdAt.getTime()) / 3600000).toFixed(0) + ' hrs ago';
    }
  },

})

var Comment = sequelize.define('comment',{
    text: Sequelize.TEXT
})

Post.hasMany(Comment)
Comment.belongsTo(Post)

Comment.hasMany(Comment)
Comment.belongsTo(Comment)

var Tag = sequelize.define('tag', {
    title: Sequelize.STRING
})

Tag.belongsToMany(Post, {through: 'PostTag'})
Post.belongsToMany(Tag, {through: 'PostTag'})


async function fillDB(){
    await sequelize.sync()
    var post1 = await Post.create( {
                            title: 'First Post',
                            text: 'First Post BLah-blah-blah'
                        })

    var post2 = await Post.create(
                        {
                            title: 'Second Post',
                            text: 'Second Post BLah-blah-blah'
                        })
    var post3 = await Post.create(
                        {
                            title: 'Third Post',
                            text: 'Third Post BLah-blah-blah'
                        })

    var comment1 = await Comment.create({text: 'test comment for first post'})
    var comment11 = await Comment.create({text: 'test comment for first comment of first post'})
    var comment12 = await Comment.create({text: 'test comment 2 for first comment of first post'})

    post1.addComment(comment1)
    comment1.addComment(comment11);
    comment1.addComment(comment12);


    var comment2 = await Comment.create({text: 'test comment for second post'})
    var comment21 = await Comment.create({text: 'test comment for first comment of second post'})
    var comment22 = await Comment.create({text: 'test comment 2 for first comment of second post'})

    comment2.addComment(comment21);
    comment21.addComment(comment22);
    post2.addComment(comment2)

    var tag1 = await Tag.create({title: 'tag1'})
    var tag2 = await Tag.create({title: 'tag2'})
    var tag3 = await Tag.create({title: 'tag3'})

    tag1.addPosts([post1, post3])
    post1.addTags([tag2])
    post2.addTags([tag2, tag3])
    tag3.addPost(post3)

}

//fillDB()
//
//
async function getData(){
    var tag1 = await Tag.findOne({
        where: {
            title: 'tag1'
        }
    })

    //console.log(await tag1.getPosts())

    for (let post of await tag1.getPosts()){
        console.log('TAG1', post.title)
    }

    var comment1 = await Comment.findOne({
        where: {
            id: 1
        }
    })

    for (let comment of await comment1.getComments()){
        console.log('comment1 sub comment:', comment.text)
        console.log('parent', (await comment.getComment()).text)
    }

    var post1 =(await comment1.getPost());

    console.log(`${post1.text} at ${post1.createdAt}`)
    console.log(await post1.tagz)
    console.log(post1.age)
}

getData()

var express = require('express');
var express_graphql = require('express-graphql');
var { buildSchema } = require('graphql');
// GraphQL schema
//
var schema = buildSchema(`
    type Query {
        post(id: Int!): Post
        comments(id: Int!): [Comment]
        subComments(id: Int!): [Comment]
    }
    type Post {
        id: Int
        title: String
        text:  String
        age:   String
        comments: [Comment]
    }
    type Comment {
        id: Int
        text:  String
    }
`);

async function getPost(args){
    let id = args.id
    //return Post.findById(id).then( post => (post.comments = post.getComments(), post) )
    let post = await Post.findById(id)
    post.comments = await post.getComments()
    return post;
}

function getPostComments(args){
    let id = args.id
    return Post.findById(id).then( post => post.getComments() )
}


async function getSubComments(args){
    let id = args.id
    //return Comment.findById(id).then( comment => comment.getComments() )
    let comment = await Comment.findById(id)
    return comment.getComments()
}


// Root resolver
var root = {
    post: getPost,
    comments: getPostComments,
    subComments: getSubComments,
};



// Create an express server and a GraphQL endpoint
var app = express();
app.use('/graphql', express_graphql({
    schema: schema,
    rootValue: root,
    graphiql: true
}));
app.listen(4000, () => console.log('Express GraphQL Server Now Running On localhost:4000/graphql'));


//query getPost($postID: Int!){
  //post(id:$postID){
    //text
  //}
//}

//query getComments($postID: Int!){
  //comments(id:$postID){
    //text
  //}
//}

//query getPostWithComments($postID: Int!){
  //post(id:$postID){
    //text
    //comments {
      //text
    //}
  //}
//}

//query getSubComments($commentID: Int!){
  //subComments(id:$commentID){
    //text
  //}
//}