fix(core): update
This commit is contained in:
parent
f13db1e422
commit
da2191bb96
@ -9,27 +9,27 @@
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"githost": "code.foss.global",
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"githost": "code.foss.global",
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"gitscope": "push.rocks",
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"gitscope": "push.rocks",
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"gitrepo": "smartstream",
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"gitrepo": "smartstream",
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"description": "simplifies access to node streams",
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"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.",
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"npmPackagename": "@push.rocks/smartstream",
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"npmPackagename": "@push.rocks/smartstream",
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"license": "MIT",
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"license": "MIT",
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"keywords": [
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"keywords": [
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"stream",
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"node.js",
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"node.js",
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"streams",
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"typescript",
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"stream manipulation",
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"stream manipulation",
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"pipeline",
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"data processing",
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"data processing",
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"pipeline",
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"async transformation",
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"async transformation",
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"event handling",
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"event handling",
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"backpressure management",
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"backpressure",
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"readable streams",
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"readable stream",
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"writable streams",
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"writable stream",
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"duplex streams",
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"duplex stream",
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"transform streams",
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"transform stream",
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"file streaming",
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"file streaming",
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"buffer streams",
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"buffer",
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"stream utilities",
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"stream utilities",
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"stream intake",
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"esm"
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"stream output"
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]
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]
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}
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}
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},
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},
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24
package.json
24
package.json
@ -2,7 +2,7 @@
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"name": "@push.rocks/smartstream",
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"name": "@push.rocks/smartstream",
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"version": "3.0.35",
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"version": "3.0.35",
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"private": false,
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"private": false,
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"description": "simplifies access to node streams",
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"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.",
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"main": "dist_ts/index.js",
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"main": "dist_ts/index.js",
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"typings": "dist_ts/index.d.ts",
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"typings": "dist_ts/index.d.ts",
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"type": "module",
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"type": "module",
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@ -51,22 +51,22 @@
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"readme.md"
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"readme.md"
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],
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],
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"keywords": [
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"keywords": [
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"stream",
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"node.js",
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"node.js",
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"streams",
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"typescript",
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"stream manipulation",
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"stream manipulation",
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"pipeline",
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"data processing",
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"data processing",
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"pipeline",
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"async transformation",
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"async transformation",
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"event handling",
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"event handling",
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"backpressure management",
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"backpressure",
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"readable streams",
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"readable stream",
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"writable streams",
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"writable stream",
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"duplex streams",
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"duplex stream",
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"transform streams",
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"transform stream",
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"file streaming",
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"file streaming",
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"buffer streams",
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"buffer",
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"stream utilities",
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"stream utilities",
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"stream intake",
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"esm"
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"stream output"
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]
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]
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}
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}
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@ -1 +1 @@
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- make sure to respect backpressure handling.
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242
readme.md
242
readme.md
@ -1,5 +1,6 @@
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```markdown
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# @push.rocks/smartstream
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# @push.rocks/smartstream
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simplifies access to node streams
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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.
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## Install
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## Install
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To install `@push.rocks/smartstream`, you can use npm or yarn as follows:
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To install `@push.rocks/smartstream`, you can use npm or yarn as follows:
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@ -14,7 +15,7 @@ This will add `@push.rocks/smartstream` to your project's dependencies.
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## Usage
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## Usage
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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.
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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.
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### Importing the Module
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### Importing the Module
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@ -24,6 +25,12 @@ Start by importing the module into your TypeScript file:
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import * as smartstream from '@push.rocks/smartstream';
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import * as smartstream from '@push.rocks/smartstream';
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```
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```
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For a more specific import, you may do the following:
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```typescript
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import { SmartDuplex, StreamWrapper, StreamIntake, createTransformFunction, createPassThrough } from '@push.rocks/smartstream';
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```
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### Creating Basic Transform Streams
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### Creating Basic Transform Streams
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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:
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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:
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@ -58,7 +65,7 @@ const processDataDuplex = new SmartDuplex({
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sourceStream.pipe(processDataDuplex).pipe(destinationStream);
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sourceStream.pipe(processDataDuplex).pipe(destinationStream);
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```
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```
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### Stream Combiners
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### Combining Multiple Streams
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`Smartstream` facilitates easy combining of multiple streams into a single pipeline, handling errors and cleanup automatically. Here's how you can combine multiple streams:
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`Smartstream` facilitates easy combining of multiple streams into a single pipeline, handling errors and cleanup automatically. Here's how you can combine multiple streams:
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@ -101,7 +108,7 @@ Consider a scenario where you need to process a large CSV file, transform the da
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```typescript
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```typescript
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import { SmartDuplex, createTransformFunction } from '@push.rocks/smartstream';
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import { SmartDuplex, createTransformFunction } from '@push.rocks/smartstream';
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import fs from 'fs';
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import fs from 'fs';
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import csvParser from 'csv-parser'; // Assume this is a CSV parsing library
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import csvParser from 'csv-parser';
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const csvReadTransform = createTransformFunction<any, any>(async (row) => {
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const csvReadTransform = createTransformFunction<any, any>(async (row) => {
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// Process row
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// Process row
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@ -121,11 +128,232 @@ fs.createReadStream('path/to/largeFile.csv')
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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.
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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.
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### Conclusion
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### Advanced Use Case: Backpressure Handling
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`@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.
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Effective backpressure handling is crucial when working with streams to avoid overwhelming the downstream consumers. Here’s a comprehensive example that demonstrates handling backpressure in a pipeline with multiple `SmartDuplex` instances:
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```typescript
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import { SmartDuplex } from '@push.rocks/smartstream';
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// Define the first SmartDuplex, which writes data slowly to simulate backpressure
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const slowProcessingStream = new SmartDuplex({
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name: 'SlowProcessor',
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objectMode: true,
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writeFunction: async (chunk, { push }) => {
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await new Promise(resolve => setTimeout(resolve, 100)); // Simulated delay
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console.log('Processed chunk:', chunk);
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push(chunk);
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}
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});
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// Define the second SmartDuplex as a fast processor
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const fastProcessingStream = new SmartDuplex({
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name: 'FastProcessor',
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objectMode: true,
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writeFunction: async (chunk, { push }) => {
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console.log('Fast processing chunk:', chunk);
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push(chunk);
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}
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});
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// Create a StreamIntake to dynamically handle incoming data
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const streamIntake = new StreamIntake<string>();
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// Chain the streams together and handle the backpressure scenario
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streamIntake
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.pipe(fastProcessingStream)
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.pipe(slowProcessingStream)
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.pipe(createPassThrough()) // Use Pass-Through to provide intermediary handling
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.on('data', data => console.log('Final output:', data))
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.on('error', error => console.error('Stream encountered an error:', error));
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// Simulate data pushing with intervals to observe backpressure handling
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let counter = 0;
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const interval = setInterval(() => {
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if (counter >= 10) {
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streamIntake.signalEnd();
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clearInterval(interval);
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} else {
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streamIntake.pushData(`Chunk ${counter}`);
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counter++;
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}
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}, 50);
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```
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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.
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### Transform Streams in Parallel
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For scenarios where you need to process data in parallel:
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```typescript
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import { SmartDuplex, createTransformFunction } from '@push.rocks/smartstream';
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const parallelTransform = createTransformFunction<any, any>(async (chunk) => {
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// Parallel Processing
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const results = await Promise.all(chunk.map(async item => await processItem(item)));
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return results;
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});
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const streamIntake = new StreamIntake<any[]>();
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streamIntake
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.pipe(parallelTransform)
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.pipe(new SmartDuplex({
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async writeFunction(chunk, { push }) {
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console.log('Processed parallel chunk:', chunk);
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push(chunk);
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}
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}))
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.on('finish', () => console.log('Parallel processing completed.'));
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// Simulate data pushing
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streamIntake.pushData([1, 2, 3, 4]);
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streamIntake.pushData([5, 6, 7, 8]);
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streamIntake.signalEnd();
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```
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### Error Handling in Stream Pipelines
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Error handling is an essential part of working with streams. The `StreamWrapper` assists in combining multiple streams while managing errors seamlessly:
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```typescript
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import { StreamWrapper } from '@push.rocks/smartstream';
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const faultyStream = new SmartDuplex({
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async writeFunction(chunk, { push }) {
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if (chunk === 'bad data') {
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throw new Error('Faulty data encountered');
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}
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push(chunk);
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}
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});
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const readStream = new StreamIntake<string>();
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const writeStream = new SmartDuplex({
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async writeFunction(chunk) {
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console.log('Written chunk:', chunk);
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}
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});
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const combinedStream = new StreamWrapper([readStream, faultyStream, writeStream]);
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combinedStream.run()
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.then(() => console.log('Stream processing completed.'))
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.catch(err => console.error('Stream error:', err.message));
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// Push Data
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readStream.pushData('good data');
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readStream.pushData('bad data'); // This will throw an error
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readStream.pushData('more good data');
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readStream.signalEnd();
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```
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### Testing Streams
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Here's an example test case using the `tap` testing framework to verify the integrity of the `SmartDuplex` from a buffer:
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```typescript
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import { expect, tap } from '@push.rocks/tapbundle';
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import { SmartDuplex } from '@push.rocks/smartstream';
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tap.test('should create a SmartStream from a Buffer', async () => {
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const bufferData = Buffer.from('This is a test buffer');
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const smartStream = SmartDuplex.fromBuffer(bufferData, {});
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let receivedData = Buffer.alloc(0);
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return new Promise<void>((resolve) => {
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smartStream.on('data', (chunk: Buffer) => {
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receivedData = Buffer.concat([receivedData, chunk]);
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});
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smartStream.on('end', () => {
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expect(receivedData.toString()).toEqual(bufferData.toString());
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resolve();
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});
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});
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});
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tap.start();
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```
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### Working with Files and Buffers
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You can easily stream files and buffers with `smartstream`. Here’s a test illustrating reading and writing with file streams using `smartfile` combined with `smartstream` utilities:
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```typescript
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import { tap } from '@push.rocks/tapbundle';
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import * as smartfile from '@push.rocks/smartfile';
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import { SmartDuplex, StreamWrapper } from '@push.rocks/smartstream';
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tap.test('should handle file read and write streams', async () => {
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const readStream = smartfile.fsStream.createReadStream('./test/assets/readabletext.txt');
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const writeStream = smartfile.fsStream.createWriteStream('./test/assets/writabletext.txt');
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const transformStream = new SmartDuplex({
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async writeFunction(chunk, { push }) {
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const transformedChunk = chunk.toString().toUpperCase();
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push(transformedChunk);
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}
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});
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const streamWrapper = new StreamWrapper([readStream, transformStream, writeStream]);
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await streamWrapper.run();
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const outputContent = await smartfile.fs.promises.readFile('./test/assets/writabletext.txt', 'utf-8');
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console.log('Output Content:', outputContent);
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});
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tap.start();
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```
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### Modular and Scoped Transformations
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Creating modular and scoped transformations is straightforward with `SmartDuplex`:
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```typescript
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import { SmartDuplex } from '@push.rocks/smartstream';
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type DataChunk = {
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id: number;
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data: string;
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};
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const transformationStream1 = new SmartDuplex<DataChunk, DataChunk>({
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async writeFunction(chunk, { push }) {
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chunk.data = chunk.data.toUpperCase();
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push(chunk);
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}
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})
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const transformationStream2 = new SmartDuplex<DataChunk, DataChunk>({
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async writeFunction(chunk, { push }) {
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chunk.data = `${chunk.data} processed with transformation 2`;
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push(chunk);
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}
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});
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const initialData: DataChunk[] = [
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{ id: 1, data: 'first' },
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{ id: 2, data: 'second' }
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];
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const intakeStream = new StreamIntake<DataChunk>();
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intakeStream
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.pipe(transformationStream1)
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.pipe(transformationStream2)
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.on('data', data => console.log('Transformed Data:', data));
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initialData.forEach(item => intakeStream.pushData(item));
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intakeStream.signalEnd();
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```
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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.
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```
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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).
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## License and Legal Information
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## License and Legal Information
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@ -3,6 +3,6 @@
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*/
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*/
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export const commitinfo = {
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export const commitinfo = {
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name: '@push.rocks/smartstream',
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name: '@push.rocks/smartstream',
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version: '3.0.35',
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version: '3.0.36',
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description: 'simplifies access to node streams'
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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.'
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}
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}
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Loading…
Reference in New Issue
Block a user