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 >= v4.0.0). 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.

npm install firstline

(add "--save" if you want the module to be automatically added to your project's "package.json" dependencies)

var firstline = require(firstline)

firstline(filepath)

Incrementally reads data from "filepath" until it reaches the end of the first line. Returns a promise, eventually fulfilled with a string.

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

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

MIT License