Using Simple Examples

In any substantial project, it is necessary to separate your code in different files. Node.js implements the CommonJS API standard to load modules from other files. Using exports can be a source of much confusion in Node.js. Let us explore how exports works.

A practical functional library for JavaScript programmers.

There are already several excellent libraries with a functional flavor. Typically, they are meant to be general-purpose toolkits, suitable for working in multiple paradigms. Ramda has a more focused goal. We wanted a library designed specifically for a functional programming style, one that makes it easy to create functional pipelines, one that never mutates user data.

A free, once–weekly e-mail round-up of JavaScript news and articles.

In JavaScript, functions are first-class objects; that is, functions are of the type Object and they can be used in a first-class manner like any other object (String, Array, Number, etc.) since they are in fact objects themselves. They can be “stored in variables, passed as arguments to functions, created within functions, and returned from functions”.

Because functions are first-class objects, we can pass a function as an argument in another function and later execute that passed-in function or even return it to be executed later. This is the essence of using callback functions in JavaScript. In the rest of this article we will learn everything about JavaScript callback functions. Callback functions are probably the most widely used functional programming technique in JavaScript, and you can find them in just about every piece of JavaScript and jQuery code, yet they remain mysterious to many JavaScript developers. The mystery will be no more, by the time you finish reading this article.

Callback functions are derived from a programming paradigm known as functional programming. At a fundamental level, functional programming specifies the use of functions as arguments. Functional programming was—and still is, though to a much lesser extent today—seen as an esoteric technique of specially trained, master programmers.

Fortunately, the techniques of functional programming have been elucidated so that mere mortals like you and me can understand and use them with ease. One of the chief techniques in functional programming happens to be callback functions. As you will read shortly, implementing callback functions is as easy as passing regular variables as arguments. This technique is so simple that I wonder why it is mostly covered in advanced JavaScript topics.

Note the following ways we frequently use callback functions in JavaScript, especially in modern web application development, in libraries, and in frameworks:


• For asynchronous execution (such as reading files, and making HTTP requests)
• In Event Listeners/Handlers
• In setTimeout and setInterval methods
• For Generalization: code conciseness

Instead of return, you should use callbacks as in asynchronous operations, return does not wait for the I/O operation to complete.

Emacs support library for PDF files.

PDF Tools is, among other things, a replacement of DocView for PDF files. The key difference is, that pages are not pre-rendered by e.g. ghostscript and stored in the file-system, but rather created on-demand and stored in memory.

This rendering is performed by a special library named, for whatever reason, poppler, running inside a server program. This program is called epdfinfo and its job is it to successively read requests from Emacs and produce the proper results, i.e. the PNG image of a PDF page.

Actually, displaying PDF files is just one part of PDF Tools. Since poppler can provide us with all kinds of information about a document and is also able to modify it, there is a lot more we can do with it.

CharMap is unicode table viewer for Emacs. With CharMap you can see the unicode table based on The Unicode Standard 6.2.

This is a complete and feature rich Redis client for node.js. It supports all Redis commands and focuses on high performance.

Install with:

npm install redis

Qtractor is an Audio/MIDI multi-track sequencer application written in C++ with the Qt framework. Target platform is Linux, where the Jack Audio Connection Kit (JACK) for audio, and the Advanced Linux Sound Architecture (ALSA) for MIDI, are the main infrastructures to evolve as a fairly-featured Linux desktop audio workstation GUI, specially dedicated to the personal home-studio.

KXStudio is a collection of applications and plugins for professional audio production.
KXStudio provides Debian and Ubuntu compatible repositories and its own Linux Distribution currently based on Ubuntu 14.04.5 LTS.

SuperCollider is a platform for audio synthesis and algorithmic composition, used by musicians, artists, and researchers working with sound. It is free and open source software available for Windows, macOS, and Linux.

Dexed is a multi platform, multi format plugin synth that is closely modeled on the Yamaha DX7. Dexed is also a midi cartridge librarian/manager for the DX7.

Full documentation for sequencer64, a loyal fork of seq24, now including native JACK MIDI in v. 0.90.0.

A major reboot of Seq24, with new features and bug fixes. Current release is 0.93.0, native JACK MIDI and ALSA, important bug fixes, new features "multi-wid" and "varisets", better support for Meta events.

Seq24 is a minimal loop based midi sequencer.

It was created to provide a very simple interface for editing and playing midi 'loops'. After searching for a software based sequencer that would provide the functionality needed for a live performance, such as the Akai MPC line, the Kawai Q80 sequencer, or the popular Alesis MMT-8, I found nothing similar in the software realm. I set out to create a very minimal sequencer that excludes the bloated features of the large software sequencers, and includes a small subset of features that I have found usable in performing.

Let's make music

with a free, cross-platform tool for your computer.