How do I approach working with IndexedDB through a Mint app?

[jiggneshhgohel]

Hello,

I am interested in implementing a Mint app abstracting an API demonstrated at https://www.javascripttutorial.net/web-apis/javascript-indexeddb/ to work with IndexedDB. How do I start with? I tried following

source/Stores/Database.mint

store Database {
  state db : Object = {}

  fun initialize : Promise(Void) {
    let openOrCreateDB = Window.indexedDB.open("todo_db", 1)

    let listener1 =
      openOrCreateDB.addEventListener("error", () : Void {
        Debug.log("Error opening DB")
      })


    let listener2 =
      openOrCreateDB.addEventListener("success", () : Promise(Void) {
        Debug.log("Successfully opened DB")

        next { db : openOrCreateDB.result }
      })
  }
}

source/Routes.mint

routes {

  / {
    Database.initialize
  }
}

but encountering following error which I am unable to understand how to fix:

ERROR (ACCESS_NOT_RECORD) 

You are trying to access a field on an entity which is not a record:

  Void

The access in question is here:

    ┌ source/Stores/Database.mint:5:26

I would like to expose an API like

Database.connect
Database.create_table
Database.table
Database.table.insert_record
Database.table.find_records
Database.table.delete_record
Database.table.disconnect

Note: I am not seeking here any step-by-step help to achieve the desired goal. I am only seeking guidance on how to translate the demonstrated vanilla JS code into Mint lang syntax.

Thanks.

[gdotdesign]

There are no bindings for IndexedDB yet. You will need to create them on your own and for that you need to fall back to JavaScript using inlining:

module IndexedDB {
  fun open(name : String) : Promise(Result(String, IndexedDB) {
    `
    new Promise((resolve) {
      const request = window.indexedDB.open(#{name});

      request.onerror = (event) => {
        resolve(#{Result.Err("Couldn't connect to database!")})
      };

      request.onsuccess = (event) => {
        resolve(#{Result.Ok(`event.target.result`)})
      };
    })
    `
  }
}

// Later...
case IndexedDB.open("test") {
  Ok(db) => // Do something with the database
  Err(error) => // Couldn't open the database
}

That ⬆️ should help you get started. The IndexedDB type is a phantom type which is not defined anywhere, but helps you make sure you only get the proper underlying object in other functions: https://mint-lang.com/reference/types/type-system

Also, here is the localStorage and sessionStorage binding which you can probably use https://github.com/mint-lang/mint/blob/master/core/source/Storage/Common.mint as a reference.

[jiggneshhgohel]

@gdotdesign Thank you very much for your prompt guidance. That is definitely very helpful to start with.