Shopify Functions

app.defineFunction() configures the OpenShop management UI and GraphQL mutations for Shopify Function instances. It does not define the WASM function implementation.

export const volumeDiscount = app.defineFunction({
  type: 'discount',
  handle: 'volume-discount',
  modes: ['automatic', 'code'],
  owner: {
    title: (config) => `Volume discount ${config.threshold}`,
    combinesWith: { productDiscounts: true },
    startsAt: true,
    endsAt: true,
  },
  config: {
    threshold: { type: 'number', label: 'Minimum quantity' },
    percentage: { type: 'number', label: 'Percentage off' },
  },
})

Supported function types

discount
cart-transform
delivery-customization
payment-customization
checkout-validation
fulfillment-constraints

Some Shopify Function types do not support update mutations. OpenShop surfaces this in the admin UI and expects delete-and-recreate for those types.