Prisma find in batches extension

README-prisma-findInBatches.md

findInBatches extension for Prisma

Prisma client extension function to find many results in batches.

NOTE: Requires Prisma 4.7.0 or later with previewFeatures = ["clientExtensions"] in schema.prisma. https://www.prisma.io/docs/concepts/components/prisma-client/client-extensions

Usage

client.MODEL_NAME.findInBatches({ maxPages: Infinity, take: 1000, ...query }, callbackFn);

Examples

// Find all users in batches with @gmail.com email
client.user.findInBatches({ where: { email: { endsWith: '@gmail.com' } } }, async (results, page) => {
  // Do something with results
});

// Find first 2000 users names and email addresses in batches of 100 skipping the first 500 users
client.user.findInBatches(
  { maxPages: 20, skip: 500, take: 100, select: { name: true, email: true } },
  async (results, page) => {
    // Do something with results
  },
);

prisma-findInBatches.js

// Initialize Prisma client
let client = new PrismaClient();

// Extend client model
client = client.$extends({
  model: {
    $allModels: {
      /**
       * Prisma find in batches query
       * @function
       * @param args {object} - Prisma query arguments
       * @param args.maxPages {integer} - Maximum page interations to make. _(default: Infinity)_
       * @param args.skip {integer} - Initial offset. _(default: 0)_
       * @param args.take {integer} - Number of items to take (limit) per batch. _(default: 1000)_
       * @param callback {function} - Callback function to process results. Receives two arguments: `results` and `page`.
       * @return {object}
       */
      async findInBatches(args, callback) {
        // Allow passing only callback function _(not recommended)_
        if (!callback && typeof args === 'function') {
          callback = args;
          args = {};
        }

        // Ensure callback function exists
        if (typeof callback !== 'function') {
          throw new Error('A callback function is required');
        }

        // Set max pages, skip offset, and take amount per batch
        const { maxPages = Infinity, skip = 0, take = 1000, ...queryArgs } = args;

        // Iterate through batches
        let count = 0;
        let pages = 0;
        while (maxPages > pages) {
          // Query model
          const results = await this.findMany({ ...queryArgs, take, skip: (take * pages) + skip });

          // Pass results to callback function
          await callback(results, pages);

          // Increment pages and counts
          count += results.length;
          pages += 1;

          // Halt if no more results
          if (take > results.length) {
            break;
          }
        }

        return { count, pages };
      },
    },
  },
});