fix(core): update

This commit is contained in:
Philipp Kunz 2024-05-17 18:13:51 +02:00
parent f13db1e422
commit da2191bb96
5 changed files with 261 additions and 33 deletions

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@ -9,27 +9,27 @@
"githost": "code.foss.global",
"gitscope": "push.rocks",
"gitrepo": "smartstream",
"description": "simplifies access to node streams",
"description": "A library to simplify the creation and manipulation of Node.js streams, providing utilities for handling transform, duplex, and readable/writable streams effectively in TypeScript.",
"npmPackagename": "@push.rocks/smartstream",
"license": "MIT",
"keywords": [
"stream",
"node.js",
"streams",
"typescript",
"stream manipulation",
"pipeline",
"data processing",
"pipeline",
"async transformation",
"event handling",
"backpressure management",
"readable streams",
"writable streams",
"duplex streams",
"transform streams",
"backpressure",
"readable stream",
"writable stream",
"duplex stream",
"transform stream",
"file streaming",
"buffer streams",
"buffer",
"stream utilities",
"stream intake",
"stream output"
"esm"
]
}
},

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@ -2,7 +2,7 @@
"name": "@push.rocks/smartstream",
"version": "3.0.35",
"private": false,
"description": "simplifies access to node streams",
"description": "A library to simplify the creation and manipulation of Node.js streams, providing utilities for handling transform, duplex, and readable/writable streams effectively in TypeScript.",
"main": "dist_ts/index.js",
"typings": "dist_ts/index.d.ts",
"type": "module",
@ -51,22 +51,22 @@
"readme.md"
],
"keywords": [
"stream",
"node.js",
"streams",
"typescript",
"stream manipulation",
"pipeline",
"data processing",
"pipeline",
"async transformation",
"event handling",
"backpressure management",
"readable streams",
"writable streams",
"duplex streams",
"transform streams",
"backpressure",
"readable stream",
"writable stream",
"duplex stream",
"transform stream",
"file streaming",
"buffer streams",
"buffer",
"stream utilities",
"stream intake",
"stream output"
"esm"
]
}

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@ -1 +1 @@
- make sure to respect backpressure handling.

242
readme.md
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@ -1,5 +1,6 @@
```markdown
# @push.rocks/smartstream
simplifies access to node streams
A TypeScript library to simplify the creation and manipulation of Node.js streams, providing utilities for transform, duplex, and readable/writable stream handling while managing backpressure effectively.
## Install
To install `@push.rocks/smartstream`, you can use npm or yarn as follows:
@ -14,7 +15,7 @@ This will add `@push.rocks/smartstream` to your project's dependencies.
## Usage
The `@push.rocks/smartstream` module is designed to simplify working with Node.js streams by providing a set of utilities for creating and manipulating streams. This module makes heavy use of TypeScript for improved code quality, readability, and maintenance. ESM syntax is utilized throughout the examples.
The `@push.rocks/smartstream` module is designed to simplify working with Node.js streams by providing a set of utilities for creating and manipulating streams. This module makes extensive use of TypeScript for improved code quality, readability, and maintenance. ESM syntax is utilized throughout the examples.
### Importing the Module
@ -24,6 +25,12 @@ Start by importing the module into your TypeScript file:
import * as smartstream from '@push.rocks/smartstream';
```
For a more specific import, you may do the following:
```typescript
import { SmartDuplex, StreamWrapper, StreamIntake, createTransformFunction, createPassThrough } from '@push.rocks/smartstream';
```
### Creating Basic Transform Streams
The module provides utilities for creating transform streams. For example, to create a transform stream that modifies chunks of data, you can use the `createTransformFunction` utility:
@ -58,7 +65,7 @@ const processDataDuplex = new SmartDuplex({
sourceStream.pipe(processDataDuplex).pipe(destinationStream);
```
### Stream Combiners
### Combining Multiple Streams
`Smartstream` facilitates easy combining of multiple streams into a single pipeline, handling errors and cleanup automatically. Here's how you can combine multiple streams:
@ -101,7 +108,7 @@ Consider a scenario where you need to process a large CSV file, transform the da
```typescript
import { SmartDuplex, createTransformFunction } from '@push.rocks/smartstream';
import fs from 'fs';
import csvParser from 'csv-parser'; // Assume this is a CSV parsing library
import csvParser from 'csv-parser';
const csvReadTransform = createTransformFunction<any, any>(async (row) => {
// Process row
@ -121,11 +128,232 @@ fs.createReadStream('path/to/largeFile.csv')
This example demonstrates reading a large CSV file, transforming each row with `createTransformFunction`, and using a `SmartDuplex` to manage the processed data flow efficiently, ensuring no data is lost due to backpressure issues.
### Conclusion
### Advanced Use Case: Backpressure Handling
`@push.rocks/smartstream` offers a robust set of tools for working with Node.js streams, providing a more intuitive and reliable way to create, manipulate, and combine streams. By leveraging TypeScript and ESM syntax, `smartstream` enables developers to build more maintainable and type-safe stream-based solutions.
Effective backpressure handling is crucial when working with streams to avoid overwhelming the downstream consumers. Heres a comprehensive example that demonstrates handling backpressure in a pipeline with multiple `SmartDuplex` instances:
```typescript
import { SmartDuplex } from '@push.rocks/smartstream';
// Define the first SmartDuplex, which writes data slowly to simulate backpressure
const slowProcessingStream = new SmartDuplex({
name: 'SlowProcessor',
objectMode: true,
writeFunction: async (chunk, { push }) => {
await new Promise(resolve => setTimeout(resolve, 100)); // Simulated delay
console.log('Processed chunk:', chunk);
push(chunk);
}
});
// Define the second SmartDuplex as a fast processor
const fastProcessingStream = new SmartDuplex({
name: 'FastProcessor',
objectMode: true,
writeFunction: async (chunk, { push }) => {
console.log('Fast processing chunk:', chunk);
push(chunk);
}
});
// Create a StreamIntake to dynamically handle incoming data
const streamIntake = new StreamIntake<string>();
// Chain the streams together and handle the backpressure scenario
streamIntake
.pipe(fastProcessingStream)
.pipe(slowProcessingStream)
.pipe(createPassThrough()) // Use Pass-Through to provide intermediary handling
.on('data', data => console.log('Final output:', data))
.on('error', error => console.error('Stream encountered an error:', error));
// Simulate data pushing with intervals to observe backpressure handling
let counter = 0;
const interval = setInterval(() => {
if (counter >= 10) {
streamIntake.signalEnd();
clearInterval(interval);
} else {
streamIntake.pushData(`Chunk ${counter}`);
counter++;
}
}, 50);
```
In this advanced use case, a `SlowProcessor` and `FastProcessor` are created using `SmartDuplex`, simulating a situation where one stream is slower than another. The `StreamIntake` dynamically handles incoming chunks of data and the intermediary Pass-Through handles any potential interruptions.
### Transform Streams in Parallel
For scenarios where you need to process data in parallel:
```typescript
import { SmartDuplex, createTransformFunction } from '@push.rocks/smartstream';
const parallelTransform = createTransformFunction<any, any>(async (chunk) => {
// Parallel Processing
const results = await Promise.all(chunk.map(async item => await processItem(item)));
return results;
});
const streamIntake = new StreamIntake<any[]>();
streamIntake
.pipe(parallelTransform)
.pipe(new SmartDuplex({
async writeFunction(chunk, { push }) {
console.log('Processed parallel chunk:', chunk);
push(chunk);
}
}))
.on('finish', () => console.log('Parallel processing completed.'));
// Simulate data pushing
streamIntake.pushData([1, 2, 3, 4]);
streamIntake.pushData([5, 6, 7, 8]);
streamIntake.signalEnd();
```
### Error Handling in Stream Pipelines
Error handling is an essential part of working with streams. The `StreamWrapper` assists in combining multiple streams while managing errors seamlessly:
```typescript
import { StreamWrapper } from '@push.rocks/smartstream';
const faultyStream = new SmartDuplex({
async writeFunction(chunk, { push }) {
if (chunk === 'bad data') {
throw new Error('Faulty data encountered');
}
push(chunk);
}
});
const readStream = new StreamIntake<string>();
const writeStream = new SmartDuplex({
async writeFunction(chunk) {
console.log('Written chunk:', chunk);
}
});
const combinedStream = new StreamWrapper([readStream, faultyStream, writeStream]);
combinedStream.run()
.then(() => console.log('Stream processing completed.'))
.catch(err => console.error('Stream error:', err.message));
// Push Data
readStream.pushData('good data');
readStream.pushData('bad data'); // This will throw an error
readStream.pushData('more good data');
readStream.signalEnd();
```
### Testing Streams
Here's an example test case using the `tap` testing framework to verify the integrity of the `SmartDuplex` from a buffer:
```typescript
import { expect, tap } from '@push.rocks/tapbundle';
import { SmartDuplex } from '@push.rocks/smartstream';
tap.test('should create a SmartStream from a Buffer', async () => {
const bufferData = Buffer.from('This is a test buffer');
const smartStream = SmartDuplex.fromBuffer(bufferData, {});
let receivedData = Buffer.alloc(0);
return new Promise<void>((resolve) => {
smartStream.on('data', (chunk: Buffer) => {
receivedData = Buffer.concat([receivedData, chunk]);
});
smartStream.on('end', () => {
expect(receivedData.toString()).toEqual(bufferData.toString());
resolve();
});
});
});
tap.start();
```
### Working with Files and Buffers
You can easily stream files and buffers with `smartstream`. Heres a test illustrating reading and writing with file streams using `smartfile` combined with `smartstream` utilities:
```typescript
import { tap } from '@push.rocks/tapbundle';
import * as smartfile from '@push.rocks/smartfile';
import { SmartDuplex, StreamWrapper } from '@push.rocks/smartstream';
tap.test('should handle file read and write streams', async () => {
const readStream = smartfile.fsStream.createReadStream('./test/assets/readabletext.txt');
const writeStream = smartfile.fsStream.createWriteStream('./test/assets/writabletext.txt');
const transformStream = new SmartDuplex({
async writeFunction(chunk, { push }) {
const transformedChunk = chunk.toString().toUpperCase();
push(transformedChunk);
}
});
const streamWrapper = new StreamWrapper([readStream, transformStream, writeStream]);
await streamWrapper.run();
const outputContent = await smartfile.fs.promises.readFile('./test/assets/writabletext.txt', 'utf-8');
console.log('Output Content:', outputContent);
});
tap.start();
```
### Modular and Scoped Transformations
Creating modular and scoped transformations is straightforward with `SmartDuplex`:
```typescript
import { SmartDuplex } from '@push.rocks/smartstream';
type DataChunk = {
id: number;
data: string;
};
const transformationStream1 = new SmartDuplex<DataChunk, DataChunk>({
async writeFunction(chunk, { push }) {
chunk.data = chunk.data.toUpperCase();
push(chunk);
}
})
const transformationStream2 = new SmartDuplex<DataChunk, DataChunk>({
async writeFunction(chunk, { push }) {
chunk.data = `${chunk.data} processed with transformation 2`;
push(chunk);
}
});
const initialData: DataChunk[] = [
{ id: 1, data: 'first' },
{ id: 2, data: 'second' }
];
const intakeStream = new StreamIntake<DataChunk>();
intakeStream
.pipe(transformationStream1)
.pipe(transformationStream2)
.on('data', data => console.log('Transformed Data:', data));
initialData.forEach(item => intakeStream.pushData(item));
intakeStream.signalEnd();
```
By leveraging `SmartDuplex`, `StreamWrapper`, and `StreamIntake`, you can streamline and enhance your data transformation pipelines in Node.js with a clear, efficient, and backpressure-friendly approach.
```
For more detailed examples and documentation, visit the [GitLab Repository](https://gitlab.com/push.rocks/smartstream) or the [GitHub Mirror](https://github.com/pushrocks/smartstream).
## License and Legal Information

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@ -3,6 +3,6 @@
*/
export const commitinfo = {
name: '@push.rocks/smartstream',
version: '3.0.35',
description: 'simplifies access to node streams'
version: '3.0.36',
description: 'A library to simplify the creation and manipulation of Node.js streams, providing utilities for handling transform, duplex, and readable/writable streams effectively in TypeScript.'
}