npm package discovery and stats viewer.

Discover Tips

  • General search

    [free text search, go nuts!]

  • Package details

    pkg:[package-name]

  • User packages

    @[username]

Sponsor

Optimize Toolset

I’ve always been into building performant and accessible sites, but lately I’ve been taking it extremely seriously. So much so that I’ve been building a tool to help me optimize and monitor the sites that I build to make sure that I’m making an attempt to offer the best experience to those who visit them. If you’re into performant, accessible and SEO friendly sites, you might like it too! You can check it out at Optimize Toolset.

About

Hi, 👋, I’m Ryan Hefner  and I built this site for me, and you! The goal of this site was to provide an easy way for me to check the stats on my npm packages, both for prioritizing issues and updates, and to give me a little kick in the pants to keep up on stuff.

As I was building it, I realized that I was actually using the tool to build the tool, and figured I might as well put this out there and hopefully others will find it to be a fast and useful way to search and browse npm packages as I have.

If you’re interested in other things I’m working on, follow me on Twitter or check out the open source projects I’ve been publishing on GitHub.

I am also working on a Twitter bot for this site to tweet the most popular, newest, random packages from npm. Please follow that account now and it will start sending out packages soon–ish.

Open Software & Tools

This site wouldn’t be possible without the immense generosity and tireless efforts from the people who make contributions to the world and share their work via open source initiatives. Thank you 🙏

© 2024 – Pkg Stats / Ryan Hefner

nexline

v1.2.2

Published

Read file, stream, string, buffer line by line without putting them all in memory. It supports cool features like `custom line separator`, `various encodings`, `reverse mode`, `iterable protocol`

Downloads

475

Readme

Nexline

npm npm npm GitHub license

Read file, stream, string, buffer line by line without putting them all in memory.
It supports cool features below.

  • Lightweight
  • Iterable protocol
  • Handle large file with small memory footprint
  • Support various input types (file, stream, string, buffer)
  • Support various encodings
  • Support reverse mode
  • Support custom, multiple line separators
  • Support multiple inputs

Why I made this?

Node.js's default readline module is great but it's pause() method does not work immediately.
I made wrapper to fix that issue before, but it was not enough.
Even if pause() works immediately, it is still inconvenient.
If I want to execute async function over line by line in large file, I have to call pause() and resume() at every line.
I needed better way to do that without putting them all in memory.

Breaking changes in 1.0.0

  • lineSeparator default value is changed from ['\n', '\r\n'] to '\n' for better performance
    • If you want to handle both CRLF and LF, set lineSeparator: ['\n', '\r\n']
  • Support reverse mode.
  • Support file descriptor as input
  • Improve performance
  • Optimize memory usage

Install with npm

Required Node.js version >= 8.0.0

npm install nexline

How to use

Use next() method

const nexline = require('nexline');

async function main () {
  const nl = nexline(...);
  
  while(true) {
    const line = await nl.next();
    console.log(line);
    if (line === null) break; // If all data is read, returns null
  }
}

Use as iterator ( Requires node >= 10 )

const nexline = require('nexline');

async function main () {
  const nl = nexline(...);

  // nexline is iterable
  for await (const line of nl) console.log(line);
}

Use file as input

  • Don't forget to close file descriptor after finish
  • You can use autoCloseFile: true to close file descriptor automatically
const nl = nexline({
  input: fs.openSync(path_to_file, 'r'),
  // autoCloseFile: true,
});

Use stream as input

const nl = nexline({
  input: fs.createReadStream(path_to_file),
});

Use string as input

const nl = nexline({
  input: 'foo\nbar\nbaz',
});

Use buffer as input

const nl = nexline({
  input: Buffer.from('foo\nbar\nbaz'),
});

Use multiple input

const nl = nexline({
  input: [
    fs.openSync(path_to_file1, 'r'),
    fs.createReadStream(path_to_file2),
    'foo\nbar\nbaz',
    Buffer.from('foo\nbar\nbaz'),
  ],
});

Use other encodings

See encodings supported by iconv-lite

const nl = nexline({
  input: fs.openSync(path_to_file, 'r'), 
  encoding: 'cp949',
});

Use other lineSeparator

const nl = nexline({
  input: 'foo;bar;baz', 
  lineSeparator: ';',
});

Use multiple lineSeparator

const nl = nexline({
  input: 'foo\r\nbar\nbaz', 
  lineSeparator: ['\n', '\r\n'], // You can handle both LF and CRLF like this.
});

Reverse mode

const nl = nexline({
  input: fs.openSync(path_to_file, 'r'), // NOTE: You cannot use stream in reverse mode. 
  reverse: true, 
});

Methods

| Name | Description | | ------------- | --------------- | | next() | async, It returns line until all data is read, after then returns null | | close() | Close nexline |

Options

| Name | Default | Description | | ------------- | --------------------------- | --------------- | | input | undefined | Required. File descriptor, stream, string, buffer, You can provide multiple inputs using array | | lineSeparator | '\n' | Any string more than one character. You can provide multiple line separator using array | | encoding | 'utf8' | See encodings supported by iconv-lite | | reverse | false | Reverse mode, Cannot use this option with stream input because stream cannot be read from end. Use file descriptor instead | | autoCloseFile | false | Automatically close file descriptor after all data is read |

Contribution

Pull requests and stars are always welcome. For bugs and feature requests, please create an issue

License

Copyright © 2019 Youngho Jin. Released under the MIT License