Registry / data / stream-transform

stream-transform

library3.4.1jsnpmunverified

Stream-transform is a robust JavaScript library designed for object transformations, implementing the Node.js `stream.Transform` API. It is a core component of the broader `node-csv` project, currently at version 3.4.1. This library offers flexible APIs, including stream-based for high scalability, and convenient callback-based and synchronous options for simpler use cases. Key differentiators include its adherence to the native Node.js stream interface, support for both synchronous and asynchronous user functions, and capabilities for sequential or concurrent execution. It can process various input and output types such as objects, arrays, and JSON, enabling operations like skipping, multiplying, altering, or cloning records. While an explicit release cadence isn't stated, its inclusion in the actively maintained `node-csv` project implies regular updates and support.

data serialization http-networking

npm install stream-transform

github ↗package ↗homepage ↗

INSTALL

IMPORT

SIG · STREAM-TRANSFORM

stream-transform

datajavascriptv3.4.1

Install

—

Import

—

Disk

—

Pass rate

0/ 6

Env Coverage0 / 6

glibc

18–22

musl

18–22

Install & Compatibility

Where this runs

tested against v? · npm install

Install × environment matrix

Each cell = how many times install + import succeeded across repeated harness runs. Partial = flaky.
glibc = Debian/Ubuntu slim · musl = Alpine Linux

musl

node 18–226 runs

build_error

glibc

node 18–226 runs

build_error

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

transform

✓ import { transform } from 'stream-transform/sync';

✗ const { transform } = require('stream-transform/sync');

This is for the synchronous API. As of v3.x, `stream-transform` is primarily an ESM module, so CommonJS `require` for ES Module paths is incorrect. It may work with specific bundler configurations or older Node.js versions, but `import` is the idiomatic way.

transform

✓ import { transform } from 'stream-transform';

✗ const transform = require('stream-transform');

This imports the factory function for the stream-based API. Named imports are standard for ESM. Attempting to `require` this path directly in an ESM context will fail.

Transformer

✓ import { Transformer } from 'stream-transform';

✗ class MyTransformer extends require('stream-transform').Transformer {}

To extend the base Transformer class for custom stream implementations, use a named import. Direct `require` for extending classes is not recommended in modern Node.js ESM.

transform (Callback API)

✓ import { transform as transformCallback } from 'stream-transform/callback';

The callback API is designed for smaller datasets that fit into memory. This specific import path is for the callback-based `transform` function.

This quickstart demonstrates the synchronous transformation API. It takes an array of arrays (records), applies a function to each record to shift its elements, and asserts the output. This API is suitable for smaller datasets that can be processed in memory.

import { transform } from "stream-transform/sync"; import assert from "node:assert"; const inputRecords = [ ["a", "b", "c", "d"], ["1", "2", "3", "4"], ["x", "y", "z", "w"] ]; const transformedRecords = transform( inputRecords, function (record) { // Example transformation: move the first element to the end record.push(record.shift()); return record; }, // Optional options object can be passed here { objectMode: true } // Assuming objectMode for array records ); assert.deepEqual(transformedRecords, [ ["b", "c", "d", "a"], ["2", "3", "4", "1"], ["y", "z", "w", "x"] ]); console.log("Transformation successful:", transformedRecords);

Debug

Known issues

breakingVersion 3.x (and `node-csv` v6.x) transitioned to ECMAScript Modules (ESM) as the primary module system. This means that `require()` statements for `stream-transform` or its sub-paths may no longer work directly or require specific Node.js `--experimental-json-modules` flags or `type: 'module'` in `package.json` for interoperability with CommonJS.

fix

Migrate your import statements to use `import` syntax (e.g., `import { transform } from 'stream-transform';`). If you must use CommonJS, ensure your environment is configured for CJS-ESM interop, or consider using older versions if migration is not feasible. For sync modules, CommonJS users previously used `require('pkg/lib/sync')` but should now use `require('pkg/sync')`.

affects: >=3.0.0

gotchaWhen using the callback or synchronous APIs (e.g., `stream-transform/sync`), the entire dataset must fit into memory. These APIs buffer all records before returning the result. For very large datasets, this can lead to out-of-memory errors.

fix

For large datasets, use the stream-based API (`import { transform } from 'stream-transform';`) which processes data in chunks, leveraging Node.js streams for memory efficiency and backpressure handling.

affects: >=1.0.0

gotchaIncorrectly mixing stream modes (objectMode vs. buffer/string mode) can lead to unexpected behavior or type errors. While `stream-transform` handles objects, piping it with streams not in `objectMode` can cause issues.

fix

Ensure `objectMode: true` is consistently set on all `stream.Transform` instances in your pipeline if you are passing JavaScript objects, not just raw buffers or strings. Verify the input/output types of connected streams.

affects: >=1.0.0

Errors

Common errors & fixes

TypeError: transform is not a function

Attempting to use `require('stream-transform')` or `require('stream-transform/sync')` in a project configured for ES Modules, or incorrect named import from an ESM package.

fix

If in an ESM project, use `import { transform } from 'stream-transform';` or `import { transform } from 'stream-transform/sync';`. If in a CJS project, ensure correct CommonJS syntax and consider that direct `require` of ESM packages can be problematic in some Node.js versions without specific configurations.

Error: The 'chunk' argument must be of type string or an instance of Buffer or Uint8Array. Received an instance of Object

A stream transformation function is receiving JavaScript objects but `objectMode` is not enabled, so it expects buffers or strings.

fix

When creating a transform stream or using the `transform` factory function with JavaScript objects (e.g., arrays, JSON objects), ensure `objectMode: true` is passed in the options: `new Transformer({ objectMode: true, transform: ... })` or `transform(records, { objectMode: true }, handler)`.

Upgrade

Version history

3.4.1latest on npm

Audit

Dependencies

No dependency data recorded yet.

Agent activity

9 hits · last 30 days

node

OpenAI (training)

Resources

githubhttps://github.com/adaltas/node-csv ↗

packagehttps://www.npmjs.com/package/stream-transform ↗

homepagehttps://csv.js.org/transform ↗