How to query pivot table in Adonis Js

Question

I have a pivot table of category_post which contains the post_id and category_id i also have Post Model

categories(){

      return this.belongsToMany('App/Models/Category')

    }

Category

posts(){

      return this.belongsToMany('App/Models/Post')

    }

i am trying to loop all the posts that belongs to a category when user visits this route localhost:3333/category/news

Answer 1

You can use lucids whereHas to get all posts from specific category.

https://adonisjs.com/docs/4.1/relationships#_wherehas

const posts = await Post
  .query()
  .whereHas('category', (builder) => {
    builder.where('slug', 'news')
  })
  .fetch()

Or if you have already loaded category, you can also eagerLoad posts for it using:

https://adonisjs.com/docs/4.1/relationships#_eager_loading

const category = await Category.query().where('slug', 'news').firstOrFail()
const posts = await category.posts().fetch()

Check docs for.wherePivot also it could be useful to you too: https://adonisjs.com/docs/4.1/relationships#_querying_pivot_table