03 February, 2025

Computed fields

Today we've released a powerful new feature to the Keel runtime - computed fields.

This allows you to have a field automatically set or calculated based on an expression. Computed fields can even reference fields in related models. For one-to-many lookups, we've introduced functions which let you aggregate related data. At present, we support SUM, MIN, MAX, AVG, MEDIAN, and COUNT aggregate functions.

See the example below.

model Order {
  fields {
    // Performing an aggregated calculation in a one-to-many lookup
    total Decimal @computed @computed(SUM(order.items.subTotal))
    // Performing an simple calculation using the total fields on this model
    vat Decimal @computed(order.total * 0.2)
    // This demonstrates how computed fields can reference other computed fields
    totalExcludingVat Decimal @computed(order.total - order.vat)
    items OrderItem[]
  }
}
 
model OrderItem {
  fields {
    order Order
    product Product
    quantity Number
    // Performing a calculation on related data in a many-to-one lookup
    subTotal Decimal @computed(orderItem.product.price * orderItem.quantity)
  }
}
 
model Product {
  fields {
    name Text
    price Decimal
  }
}

Changes to expressions

We've also made a few minor breaking changes to the expression syntax. We kindly ask that you consult the two changes listed below and make the necessary updates to your schema.

&& and || operators

We'e replaced the and and or operators with && and || respectively. The behaviour is the exact same except now the syntax is now more consistent with other languages.

not in deprecated

The not in operator has been deprecated. In order to achieve the same result, we suggest that you use the negation, ! operator. For example, !(ctx.identity in team.members.identity)

Please make sure to update your CLI by running npm install -g keel.

For any issues or feedback, please visit the support channel on our community Discord (opens in a new tab) or contact us at help@keel.so.

Thank you for using Keel!