Add pg-transaction module

.eslintrc

@@ -4,7 +4,7 @@
   "extends": ["eslint:recommended", "plugin:prettier/recommended", "prettier"],
   "ignorePatterns": ["node_modules", "coverage", "packages/pg-protocol/dist/**/*", "packages/pg-query-stream/dist/**/*"],
   "parserOptions": {
-    "ecmaVersion": 2017,
+    "ecmaVersion": 2022,
     "sourceType": "module"
   },
   "env": {
@@ -30,6 +30,15 @@
       "rules": {
         "no-undef": "off"
       }
+    },
+    {
+      "files": ["packages/pg-transaction/src/**/*.ts"],
+      "parser": "@typescript-eslint/parser",
+      "parserOptions": {
+        "ecmaVersion": 2022,
+        "sourceType": "module",
+        "project": "./packages/pg-transaction/tsconfig.eslint.json"
+      }
     }
   ]
 }

.github/workflows/ci.yml

@@ -20,6 +20,7 @@ jobs:
           cache: yarn
       - run: yarn install --frozen-lockfile
       - run: yarn lint
+
   build:
     timeout-minutes: 15
     needs: lint
@@ -38,7 +39,6 @@ jobs:
       fail-fast: false
       matrix:
         node:
-          - '16'
           - '18'
           - '20'
           - '22'
@@ -73,4 +73,6 @@ jobs:
           node-version: ${{ matrix.node }}
           cache: yarn
       - run: yarn install --frozen-lockfile
-      - run: yarn test
+      - name: Run tests (skip pg-transaction under Node < 18)
+        run: |
+          yarn test

package.json

@@ -20,15 +20,17 @@
     "lint": "eslint --cache 'packages/**/*.{js,ts,tsx}'"
   },
   "devDependencies": {
+    "@types/node": "^20.0.0",
     "@typescript-eslint/eslint-plugin": "^7.0.0",
-    "@typescript-eslint/parser": "^6.17.0",
+    "@typescript-eslint/parser": "^7.0.0",
     "eslint": "^8.56.0",
     "eslint-config-prettier": "^10.1.2",
     "eslint-plugin-node": "^11.1.0",
     "eslint-plugin-prettier": "^5.1.2",
     "lerna": "^3.19.0",
     "prettier": "3.0.3",
-    "typescript": "^4.0.3"
+    "ts-node": "^10.9.0",
+    "typescript": "^5.2.0"
   },
   "prettier": {
     "semi": false,

packages/pg-transaction/package.json

@@ -0,0 +1,25 @@
+{
+  "name": "pg-transaction",
+  "version": "2.0.0",
+  "main": "dist/index.js",
+  "license": "MIT",
+  "scripts": {
+    "build": "tsc",
+    "start": "node dist/index.js",
+    "pretest": "tsc",
+    "test": "mocha dist/**/*.test.js"
+  },
+  "dependencies": {
+    "@types/node": "^20.0.0",
+    "typescript": "^5.8.3"
+  },
+  "engines": {
+    "node": ">=18.0.0"
+  },
+  "devDependencies": {
+    "@types/mocha": "^10.0.10",
+    "@types/pg": "^8.10.9",
+    "mocha": "^10.8.2",
+    "pg": "^8.11.3"
+  }
+}

packages/pg-transaction/src/index.test.ts

@@ -0,0 +1,74 @@
+import { strict as assert } from 'assert'
+import { Client } from 'pg'
+import { transaction } from '.'
+
+class DisposableClient extends Client {
+  // overwrite the query method and log the arguments and then dispatch to the original method
+  override query(...args: any[]): any {
+    // console.log('Executing query:', ...args);
+    // @ts-ignore
+    return super.query(...args)
+  }
+
+  async [Symbol.asyncDispose]() {
+    await this.end()
+  }
+}
+
+async function getClient(): Promise<DisposableClient> {
+  const client = new DisposableClient()
+  await client.connect()
+  await client.query('CREATE TEMP TABLE test_table (id SERIAL PRIMARY KEY, name TEXT)')
+  return client
+}
+
+describe('transaction', () => {
+  it('should create a client with an empty temp table', async () => {
+    await using client = await getClient()
+    const { rowCount } = await client.query('SELECT * FROM test_table')
+    assert.equal(rowCount, 0, 'Temp table should be empty on creation')
+  })
+
+  it('automatically commits on success', async () => {
+    await using client = await getClient()
+
+    const result = await transaction(client, async () => {
+      await client.query('INSERT INTO test_table (name) VALUES ($1)', ['test'])
+      const { rows } = await client.query('SELECT * FROM test_table')
+      return rows[0].name // Should return 'test'
+    })
+
+    assert.equal(result, 'test')
+  })
+
+  it('automatically rolls back on error', async () => {
+    await using client = await getClient()
+
+    // Assert that the transaction function rejects with the expected error
+    await assert.rejects(
+      async () => {
+        await transaction(client, async () => {
+          await client.query('INSERT INTO test_table (name) VALUES ($1)', ['test'])
+          await client.query('SELECT * FROM test_table')
+          throw new Error('Simulated error') // This will trigger a rollback
+        })
+      },
+      {
+        name: 'Error',
+        message: 'Simulated error',
+      }
+    )
+
+    // Verify that the transaction rolled back
+    const { rowCount } = await client.query('SELECT * FROM test_table')
+    assert.equal(rowCount, 0, 'Table should be empty after rollback')
+  })
+
+  it('can return nothing from the transaction with correct type', async () => {
+    await using client = await getClient()
+
+    const _: void = await transaction(client, async () => {
+      await client.query('INSERT INTO test_table (name) VALUES ($1)', ['test'])
+    })
+  })
+})

packages/pg-transaction/src/index.ts

@@ -0,0 +1,42 @@
+import { Client } from 'pg'
+
+async function doTransaction(client: Client) {
+  await client.query('BEGIN')
+
+  let shouldRollback = false
+  let disposed = false
+
+  return {
+    async [Symbol.asyncDispose]() {
+      if (disposed) return
+      disposed = true
+
+      if (shouldRollback) {
+        await client.query('ROLLBACK')
+      } else {
+        await client.query('COMMIT')
+      }
+    },
+
+    rollback() {
+      shouldRollback = true
+    },
+  }
+}
+
+// Auto-rollback wrapper that catches errors automatically
+async function transaction<T>(client: Client, fn: () => Promise<T>): Promise<T> {
+  await using txn = await doTransaction(client)
+
+  try {
+    const result = await fn()
+    // If we get here, success - transaction will auto-commit
+    return result
+  } catch (error) {
+    // If error occurs, mark for rollback
+    txn.rollback()
+    throw error
+  }
+}
+
+export { transaction as transaction }

packages/pg-transaction/tsconfig.eslint.json

@@ -0,0 +1,16 @@
+{
+  "compilerOptions": {
+    "target": "es2022",
+    "module": "commonjs",
+    "lib": ["es2022"],
+    "outDir": "./dist",
+    "rootDir": "./src",
+    "declaration": true,
+    "esModuleInterop": true,
+    "forceConsistentCasingInFileNames": true,
+    "strict": true,
+    "skipLibCheck": true
+  },
+  "include": ["src/**/*"],
+  "exclude": ["node_modules", "dist", "test"]
+}

packages/pg-transaction/tsconfig.json

@@ -0,0 +1,16 @@
+{
+  "compilerOptions": {
+    "target": "es2022",
+    "module": "commonjs",
+    "lib": ["es2022", "ESNext.Disposable"],
+    "outDir": "./dist",
+    "rootDir": "./src",
+    "declaration": true,
+    "esModuleInterop": true,
+    "forceConsistentCasingInFileNames": true,
+    "strict": true,
+    "skipLibCheck": true
+  },
+  "include": ["src/**/*"],
+  "exclude": ["node_modules", "dist", "test"]
+}