Hands On Node File System Exercise #3

gistfile1.js

var fs = require('fs');

function readBytes(filePosition, length) {
    var readFile = function(err, fd) {
        if (err) {
            console.log(err.message);
            return;
        }

        var readBuffer = new Buffer(length);
        var bufferOffset = 0;
        var bufferLength = readBuffer.length;
        
        fs.read(fd, readBuffer, bufferOffset, bufferLength, filePosition, function(err, readBytes) {
            if (err) {
                throw err;
            }

            if (readBytes > 0) {
                console.log(readBuffer.slice(0, readBytes).toString());
            }
        });
    };

    return readFile;
}

fs.open('./a.txt', 'r', readBytes(5, 5));
fs.open('./a.txt', 'r', readBytes(10, 5));