Prisma migrate down

migrate-down.ts

import { exec } from 'child_process';
import { log } from 'console';
import * as fs from 'fs';
import * as path from 'path';
import { Client } from 'pg'; // Assuming you have 'pg' npm package installed.
import * as util from 'util';


const execPromise = util.promisify(exec);

const executeMigrationDown = async (migrationPath: string) => {
  const { stdout, stderr } = await execPromise(
    `npx prisma db execute --file ${migrationPath} --schema prisma/schema.prisma`,
  );
  log('Output:', stdout);
  if (stderr) {
    console.error('Error:', stderr);
  }
};

const deletePrismaMigrationEntry = async (
  migrationName: string,
  client: Client,
) => {
  const deleteQuery = `DELETE FROM "_prisma_migrations" WHERE "migration_name" = $1`;
  await client.query(deleteQuery, [migrationName]);
};

const runDownMigrations = async (n: number) => {
  const migrationsDir = path.join(process.cwd(), 'prisma', 'migrations');
  const client = new Client({
    connectionString: process.env.DATABASE_URL,
  });
  try {
    await client.connect();
    const migrationFolders = fs
      .readdirSync(migrationsDir)
      .filter((folder) => folder !== 'migration_lock.toml')
      .sort()
      .reverse()
      .slice(0, n);
    /* eslint-disable no-restricted-syntax */
    for (const folder of migrationFolders) {
      const downScriptPath = path.join(migrationsDir, folder, 'down.sql');
      if (fs.existsSync(downScriptPath)) {
        log(`Running down migration for: ${folder}`);
        // eslint-disable-next-line no-await-in-loop
        await executeMigrationDown(downScriptPath);
        log(`Deleting Prisma migration entry for: ${folder}`);
        // eslint-disable-next-line no-await-in-loop
        await deletePrismaMigrationEntry(folder, client);
      } else {
        log(`No down.sql found for migration: ${folder}`);
      }
    }
  } catch (error) {
    console.error('An error occurred:', error);
  } finally {
    await client.end();
  }
};

const n = Number(process.argv[2]) || 0;
if (n === 0) {
  console.error('Please specify the number of migrations to run down.');
  process.exit(1);
}
void runDownMigrations(n);