How to increment property per document in Sanity?

Question

We are making a system where users can submit orders. Orders have an incrementing property deliveryNumber; a new order should get a deliveryNumber that is one higher than the previous order.

Is there any built-in support for this in Sanity?
If not, how can we achieve this, without risking collisions due to race conditions?

Answer 1

I just rediscovered this question and thought I should update it, as there has (for some time now) been a way to do exactly what you're asking:

Here's an example using the Sanity Javascript client:

const sanityClient = require('@sanity/client')
const client = sanityClient({
  projectId: 'my-project-id',
  dataset: 'my-dataset',
  token: 'sanity-auth-token',
  useCdn: false
})

client
  .patch('order-123') // Document ID to patch
  .inc({deliveryNumber: 1}) // Increment field by 1
  .commit() // Perform patch and return a promise
  .then(updatedOrder => {
    console.log('Order delivery number', updatedOrder.deliveryNumber)
  })
  .catch(err => {
    console.error('Ouch. Update failed: ', err.message)
  })

If you're not accessing Sanity via Javascript, you can do the same thing using the HTTP API.