Resolved: How to Use Sequelize Class in Front-end TypeScript Code

Question:

I have my Sequelize models set up and working. Here’s a simplified example how how I’ve done it:

//--- db.ts ---
export function db(): Sequelize{
  const sequelize = new Sequelize({
    dialect: 'sqlite',
    storage: 'DB.sqlite'
  })

  Thing.init({
    name:{ type: DataTypes.STRING },
  }, {
    sequelize //connection instance
  })
  
  return sequelize
}

export class Thing extends Model{}

I want to be able to use the Thing data type throughout my app on both the front-end and back-end so that I get nice TypeScript support in VS Code for the properties available on my class.
But when I do this in my front-end code (which happens to be Svelte) I get a type error:

<script lang="ts">
import type { Thing } from '$lib/db'

var thingOne:Thing? = null //<-- !! JSDoc types can only be used inside documentation comments !!
</script>

I also get crazy errors and behavior if I ever try and do this:

var newThing = new Thing() 
//Build failure: Could not resolve "pg-hstore" (Sequelize may be choking since I don't use Postgres)

I'm relatively new to TypeScript and Sequelize. Am I not allowed to use my Thing class throughout my front and back-end JS?

Answer:

Sequelize wants access to the database (via NodeJS api's) and is not available in the Frontend.
A type import: import type { Thing } from "$lib/db"; should be allowed, this statement is removed after typescript compilation.
But is it only for type checking, and because real class can't be used it's not very useful.

If you have better answer, please add a comment about this, thank you!

Resolved: How to Use Sequelize Class in Front-end TypeScript Code

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