Bookshelf.js 与 json 中的属性的外键关系

Question

I have 2 models

• Book: id, name, data (json)
• Author: id, name

I want to extend Book model with method author which return the author when query withRelated . This could be easy to achieve with below snippet, provided that I have author_id in Book

const Book = bookshelf.model('Book', {
  tableName: 'books',
  author() {
    return this.belongsTo('Author', 'author_id', 'id')
  }
})

But the problem is, author_id is a property of data (which is json type). I tried the snippet below but it not worked

const Book = bookshelf.model('Book', {
  tableName: 'books',
  author() {
    return this.belongsTo('Author', `data->>'author_id'`, 'id')
  }
})

If I am not allowed to have any changes in the origin models, how could I get author in this case? Thanks in advance.

Answer 1

Came up with a solution that worked, a little bit tricky combination of related and event hook

const Book = bookshelf.model('Book', {
  tableName: 'books',
  initialize: function() {
    this.on('fetched', async function(model) {
      model.set('author_id', (model.get('data') || {}).author_id || null)
      const author = await model.related('author').fetch()
      model.set('author', author)
    })
  },
  author() {
    return this.belongsTo('Author')
  }
})