Firefox history addon - stores date, page title, & page URL as you visit the page

index.js

// Libraries and objects
// Run the logURL function when tab is "ready"
require("sdk/tabs").on("ready", logURL);

// Not exactly sure what this is/does, but it's there.
var {Cu} = require("chrome");

// To read & write content to file
var {TextDecoder, TextEncoder, OS} = Cu.import("resource://gre/modules/osfile.jsm", {});

// Get the full path of the user's home directory + the filename firefoxHistory
var path = OS.Path.join(OS.Constants.Path.homeDir, 'firefoxHistory');

function logURL(tab)
{
    // Used for making date human-readable vs Epoch/Unix type
    // Currently disabled because we're using Epoch/Unix type date
    // const dateObj = new Date();
    // var curDate = dateObj.getMonth() + "/" + dateObj.getDay() + "/" +
    //     dateObj.getFullYear() + "_" + dateObj.getHours() + ":" +
    //     dateObj.getMinutes() + ":" + dateObj.getSeconds() + ":" +
    //     dateObj.getMilliseconds();

    // Lets us get the current UTC epoch/Unix-type date
    var epochDate = new Date();
    // TextEncoder/TextDecoder objects
    var encoder = new TextEncoder();

    // Get the current UTC date & convert it to seconds instead of milliseconds
    epochDate = (epochDate.getTime() / 1000).toString();
    // Dividing by 1000 to convert seconds to milliseconds leaves a remainder, let's remove that
    epochDate = epochDate.slice(0, epochDate.indexOf('.'));

    // Prepare the text to be written
    var toWrite = epochDate + "-\"" + tab.title + "\"-" + tab.url + "\n";

    var textEncoded = TextEncoder().encode(toWrite);

    // This code takes care of appending the new data to the file instead of overwriting it
    OS.File.open(path, {write: true, append: true}).then(valOpen => {

        var textEncoded = TextEncoder().encode(toWrite);

        valOpen.write(textEncoded).then(valWrite => {

            valOpen.close()

        });
    });
}