Firstline

Introduction

Firstline is a npm async module for NodeJS, that reads and returns the first line of any file. It uses native JS promises and streams (requires Node >= v6.4.0). It is well tested and built for high performance.

It is particularly suited when you need to programmatically access the first line of a large amount of files, while handling errors if they occur.

Install

npm install firstline

Usage

firstline(filePath, [opts])

• filePath (String): the full path to the file you want to read.
• opts (Object, optional):
  • encoding (String), set the file encoding (must be supported by Node.js).
  • lineEnding (String), the character used for line ending (defaults to \n).

Incrementally reads data from filePath until it reaches the end of the first line.

Returns a promise, eventually fulfilled with a string.

Examples

// Imagine the file content is:
// abc
// def
// ghi
//

firstline('./my-file.txt');
// -> Returns a promise that will be fulfilled with 'abc'.

firstline('./my-file.txt', { lineEnding: '\r' });
// -> Same as above, but using '\r' as line ending.

MIT License