@stdlib/process-read-stdin

What is @stdlib/process-read-stdin?

@stdlib/process-read-stdin is a Node.js package that provides utilities for reading from the standard input (stdin) stream. It is particularly useful for command-line applications and scripts that need to process input provided by the user or piped from other commands.

What are @stdlib/process-read-stdin's main functionalities?

Read Entire Input

This feature allows you to read the entire input from stdin at once. The callback function receives any error that occurred and the data read from stdin.

const stdin = require('@stdlib/process-read-stdin');

stdin(function (error, data) {
  if (error) {
    console.error('Error reading stdin:', error);
    return;
  }
  console.log('Data:', data.toString());
});

Read Input Line by Line

This feature allows you to read the input from stdin and process it line by line. The input data is split into lines, and each line is processed individually.

const stdin = require('@stdlib/process-read-stdin');

stdin(function (error, data) {
  if (error) {
    console.error('Error reading stdin:', error);
    return;
  }
  const lines = data.toString().split('\n');
  lines.forEach((line, index) => {
    console.log(`Line ${index + 1}: ${line}`);
  });
});

Other packages similar to @stdlib/process-read-stdin

get-stdin

The 'get-stdin' package is a simple utility for reading stdin in Node.js. It provides a promise-based API for reading the entire stdin input. Compared to @stdlib/process-read-stdin, 'get-stdin' is more focused on simplicity and ease of use, but it does not offer as many features for processing input line by line.

readline

The 'readline' module is a built-in Node.js module that provides an interface for reading data from a Readable stream (such as stdin) one line at a time. It is more flexible and powerful than @stdlib/process-read-stdin, but also more complex to use. It is suitable for applications that need fine-grained control over input processing.

read

The 'read' package is a simple utility for reading user input from stdin, with support for prompting the user and hiding input (useful for passwords). It is more interactive compared to @stdlib/process-read-stdin, which is more focused on reading piped input or input provided all at once.

README

About stdlib...

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To join us in bringing numerical computing to the web, get started by checking us out on GitHub, and please consider financially supporting stdlib. We greatly appreciate your continued support!

stdin

Read data from stdin.

Installation

npm install @stdlib/process-read-stdin

Usage

var stdin = require( '@stdlib/process-read-stdin' );

stdin( [encoding,] clbk )

Reads data from stdin.

function onRead( error, data ) {
    if ( error ) {
        return console.error( 'Error: %s', error.message );
    }
    console.log( data.toString() );
    // => '...'
}

stdin( onRead );

By default, returned data is a Buffer. To return a string of a specified encoding, provide an encoding parameter.

function onRead( error, data ) {
    if ( error ) {
        return console.error( 'Error: %s', error.message );
    }
    console.log( data );
    // => '...'
}

stdin( 'utf8', onRead );

When a file's calling Node.js process is running in a TTY context (i.e., no stdin), data will either be an empty Buffer (no encoding provided) or an empty string (encoding provided).

var stream = require( '@stdlib/streams-node-stdin' );

function onRead( error, data ) {
    if ( error ) {
        return console.error( 'Error: %s', error.message );
    }
    console.log( data );
    // => ''
}

stream.isTTY = true;

stdin( 'utf8', onRead );

Examples

var string2buffer = require( '@stdlib/buffer-from-string' );
var stream = require( '@stdlib/streams-node-stdin' );
var stdin = require( '@stdlib/process-read-stdin' );

function onRead( error, data ) {
    if ( error ) {
        console.error( 'Error: %s', error.message );
    } else {
        console.log( data.toString() );
        // => 'beep boop'
    }
}

// Fake not being in a terminal context:
stream.isTTY = false;

// Provide a callback to consume all data from `stdin`:
stdin( onRead );

// Push some data to `stdin`:
stream.push( string2buffer( 'beep' ) );
stream.push( string2buffer( ' ' ) );
stream.push( string2buffer( 'boop' ) );

// End the stream:
stream.push( null );

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Notice

This package is part of stdlib, a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.

For more information on the project, filing bug reports and feature requests, and guidance on how to develop stdlib, see the main project repository.

Community

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License

See LICENSE.

Copyright

Copyright © 2016-2024. The Stdlib Authors.