Unable to sort or filter by productVariant's price

Describe the bug I’m writing a frontend for Vendure backed website. I was using 0.17 version from @vendure/create with stock items, on SQLite. For some reason I couldn’t get it to work after PC reboot, so I have recreated repository using create. Now it’s running version 0.18 and my previous queries don’t work. I looked through Changelog and Blog but I don’t see a direct or indirect tip that this should break.

To Reproduce My query:

query ProductsForCollection(
  $slug: String
  $filters: ProductVariantFilterParameter
  $sort: ProductVariantSortParameter
) {
  collection(slug: $slug) {
    name
    slug
    description
    productVariants(options: { filter: $filters, sort: $sort }) {
      items {
        product {
          name
          assets {
            name
            source
          }
          id
          slug
          description
        }
        price
      }
      totalItems
    }
  }
}

Example variables:

• when only slug is provided it works.
• when sort like below is provided it throws

{"variables":{"slug":"electronics","filters":{},"sort":{"price":"ASC"}}}

Expected behavior It should filter / sort properly I believe.

Environment (please complete the following information):

• @vendure/core version: 0.18.1
• Nodejs version: 14.15.0
• Database (mysql/postgres etc): SQLite

Additional context Fanatastic work on the software. It’s exactly how I would’ve thought it out, but probably couldn’t build. 😃

[michaelbromley]

All sorting & filtering queries are auto-generated by the ListQueryBuilder class.

This works by introspecting the TypeORM column metadata (getColumnMetadata()) and dynamically builds a query using the TypeORM QueryBuilder interface.

So the problem comes when we have e.g. the price field of ProductVariant: https://github.com/vendure-ecommerce/vendure/blob/ae07134185e53b557c88488b475c18c59eb39e35/packages/core/src/entity/product-variant/product-variant.entity.ts#L72-L78

This is a getter, calculated at run-time (this is necessary because the actual price is channel-dependent and lives in another table, ProductVariantPrice).

So when introspecting TypeORM column metadata, there is no “price” column, hence the error.

Now, since those calculated fields can contain arbitrary JS logic to come up with the values, it’s not possible to create some automatic way to know how to sort based on that field. E.g. with the ProductVariant.price, what we really need to do is JOIN the ProductVariantPrice table, and then sort based on the value of ProductVariantPrice.price.

So my current idea is to implement some way of defining the custom sorting/filtering logic associated with each calculated field (actually, only those calculated fields which return primitive values). This might be in the form of a function which returns parameters understood by the TypeORM QueryBuilder API.

Then, the ListQueryBuilder can use that custom function when it needs to sort on that field. That’s the high-level idea, the implementation will probably be quite difficult to get right. In some instances (e.g. the Order.totalQuantity field) it will be really challenging to implement I think.

Any other ideas welcome!

[michaelbromley]

Got it. Hmm yeah there might be a regression here, I’ll look into it!