Auto-incrementing number field on collection

[zubricks]

To do this, we'd need to build something like an autoIncrement field prop. We could check the database for the most recently created document, and then take its field value and increment that.

Marking as planned and logging here for visibility.

[DanRibbens]

Duplicate of #1026

[thgh]

Here is some inspiration

[Skarema]

If anyone else is looking for this, here's how I did it:

Field:

{
  name: 'subscriptionId',
  label: 'Subscription ID',
  type: 'number',
  unique: true,
  admin: {
    readOnly: true,
  },
  custom: {
    increment: true,
    firstIncrementNummber: 1,
  }
}

Collection hook:

hooks: {
  beforeChange: [autoIncrement],
}

Function:

import { CollectionBeforeChangeHook } from 'payload/types'
import payload from "payload";

const autoIncrement: CollectionBeforeChangeHook = async ({ data, operation, req }) => {
  if (operation === 'create') {
    // Get collection name
    const collectionSlug = req.collection.config.slug;
    
    // Get all fields with custom: {increment: true}
    const incrementFields = req.collection.config.fields.filter(doc => doc.custom && doc.custom.increment === true && doc.type === 'number');
    
    // Function handling the actual incrementation
    const incrementValue = async (fieldName: string, firstIncrementNummber: number) => {
    
    // Get the last document in the collection
    const lastDocument = await payload.find({ collection: collectionSlug, sort: "-" + fieldName, limit: 1 });
    
    // Set the increment value for the new document
    return lastDocument?.docs[0]?.[`${fieldName}`] ? lastDocument?.docs[0]?.[`${fieldName}`] + 1 : firstIncrementNummber;
  }

  // Calling incrementValue function for each increment field
  for (var incrementField of incrementFields) {
    if (incrementField?.type === 'number') {
      const firstIncrementNummber = incrementField.custom.firstIncrementNummber || 1;
      const value = await incrementValue(incrementField.name, firstIncrementNummber);
      data[`${incrementField.name}`] = value;
      }
    }
  }
  return data;
};

export default autoIncrement;