---
title: "A second editor in RStudio"
author: "Stéphane Laurent"
date: '2020-10-17'
tags: R, shiny, javascript
output:
  md_document:
    variant: markdown
    preserve_yaml: true
  html_document: 
    highlight: tango
    theme: cosmo
highlighter: pandoc-solarized
---

Last month, my package [shinyMonacoEditor](https://github.com/stla/shinyMonacoEditor)
has been published on CRAN. This package provides a code editor as a Shiny app. 
It is powered by [Monaco editor](https://microsoft.github.io/monaco-editor/), an 
amazing JavaScript library better known for powering the Microsoft 'VS code' editor. 

![](https://raw.githubusercontent.com/stla/shinyMonacoEditor/master/inst/screenshots/shinyMonacoEditor.gif)
While developing this app I really had fun and I improved my modest JavaScript 
skills. It works fine but it is rather a proof of concept. Indeed, if you want 
to enjoy the Monaco editor, it is better to use 'VS code'. Even though 
`shinyMonacoEditor` makes available some features in addition to the built-ins 
features of the Monaco editor, it is not an essential tool for code development.

Recently I developed two HTML widgets which also are code editors: 
[aceEditor](https://github.com/stla/aceEditor) and 
[monaco](https://github.com/stla/monaco). They have less features than 
`shinyMonacoEditor`, because you cannot communicate with R from a HTML widget, 
and you cannot run a system command. For example, `shinyMonacoEditor` allows 
to reformat a `C++` file with the help of the command line utility 
`clang-format`. Again, this is just a proof of concept; if you want a tool to 
prettify some code, I would rather recommend my package 
[prettifyAddins](https://github.com/stla/prettifyAddins) (available on CRAN).

The HTML widgets are less funny but more practical. They really provide a 
second editor in RStudio: you can open them in the viewer pane and they don't 
lock RStudio, contrary to a Shiny app. 

![](https://raw.githubusercontent.com/stla/monaco/main/inst/screenshots/monacoJS.gif)

The `aceEditor` widget is powered by Ace editor, the JavaScript library also 
used by RStudio. It has support for 150 languages (syntax highlighting and 
snippets). It provides diagnostics for JavaScript and CSS but those tools are 
now quite old and provide false positive errors for more modern usages. I added 
the possibility to prettify or reformat the code for some languages, with the 
help of [Prettier](https://prettier.io/).

The `monaco` widget is powered by Monaco editor. It has support for 50 languages, 
particularly good for JavaScript. I have not submitted it to CRAN yet. I 
submitted `aceEditor` last week but there is a more recent version in my 
Github repo. If you want to try it now, run:

```r
remotes::install_github("stla/aceEditor@browsable")
```

The Ace *diff* editor is implemented in this version. It allows to highlight 
the differences between two files (if you want a tool to also *merge* two 
files, give a try to my other package
[shinyMergely](https://github.com/stla/shinyMergely), available on CRAN).