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    0.9.2 • Public • Published

    P5.js Server

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    New feature: “airplane mode”. The server caches requests to known CDN servers (JSDelivr, Skypack, Unpkg). A sketch that uses libraries from these servers – as the files that this package generates do — can run without an internet connection, after the cache is warmed. See here for more details.

    p5-server is a development server for p5.js. It provides a web server with live reload, and command-line tools to generate HTML and JavaScript templates. The server can serve JavaScript-only sketches (that do not require an HTML file); it figures out which libraries a sketch needs in order to run.

    Directory listing in the browser

    p5-server can be used to develop sketches; or to browse a collection of sketches in a directory.

    Using the split view to explore a collection of sketches. Click to see a higher-resolution version.

    p5-server can also be used to create a set of HTML pages that present a collection of sketches. The examples page of the p5.vectorArguments documentation demonstrates this.

    The web server, library inference, and sketch generation features are also available as a Visual Studio Code extension, and via a programmatic API.


    • Live reload. The browser reloads the page when the source is modified.

    • JavaScript-only sketches. A sketch can be a single JavaScript file. You don't need to create an HTML file just to run the sketch.

    • Automatic includes. If a JavaScript-only sketch uses a function from one of these libraries, the library will be included. (This page describes how this works.)

    • In-browser syntax errors. A JavaScript file that has a syntax error will display the error in the browser. Edit and save the file to reload the page.

      Syntax error reported in browser Syntax error reported in browser split-view

    • Sketch-aware directory listings. Viewing a directory in the browser lists the sketches, folders, other files in that directory.

    • Sketch file generation. p5 generate creates a sketch file that you can use to get started.

    • Integrated web accelerator (CDN Cache). The server proxies requests to the common content delivery networks (CDNs) that are used to deliver the sources to p5.js and common p5.js libraries. See here for more information about how this works.

    Quick Start – Installation

    These commands install the p5 command on your computer. You only need to do them once.

    Text shown in monospace should be entered into a terminal.

    1. node --version

      This tests whether Node.js is installed on your system. It should print something like v16.9.0. (The exact number doesn't matter; you just want it not to report an error such as "command not found".)

      If Node.js is not installed, install it from here. It doesn't matter whether you install the LTS or Current version of node.

    2. npm install -g p5-server

      This installs the p5 command on your computer.

      Once this is done, you can enter commands such as p5 create and p5 serve, or just p5 to see a list of all the commands.

    Quick Start – Usage

    1. p5 create my-sketch

      This creates a sketch named my-sketch.js in the current directory.

      If you already have some sketches on your file system, you can skip this step. Instead, use the cd command to change the terminal's current directory to a directory that contains some sketches.

    2. p5 serve --open

      This starts the server, and opens your sketch directory in the browser.

      Click on a sketch in the browser page to run it.

    3. Use a code editor (such as Atom, Visual Studio Code, vim, or emacs) to edit the my-sketch.js file that you created in step 1. Each time you save the file, the browser will reload the page and re-run your sketch.


    Run the Server

    p5 server

    Starts a web server that knows about p5.js sketches, and that reloads sketches when files are changed. The server is set to serve files from the current directory.

    Serve a directory inside the current directory

    p5 server PATH

    Starts a server that serves files from the directory at PATH.

    Open the browser automatically

    p5 server --open

    Starts the server, and opens the directory in the default browser.

    Browse directories in split mode

    p5 server --theme grid

    Displays directory listings in grid view.

    You can combine options, e.g. p5 server examples --theme grid --open.

    Create a sketch file

    • p5 create creates a JavaScript sketch file named sketch.js in the current directory.

      This is a JavaScript-only sketch. The server can run this sketch, or you can paste it into online editors such as the P5 web editor and

    • p5 create my-sketch.js creates a JavaScript sketch file named my-sketch.js.

    • p5 create my-sketch.html creates an HTML file named my-sketch.html and a JavaScript file named my-sketch.js.

    • p5 create my-sketch creates a folder named my-sketch, and creates index.html and sketch.js files inside this folder.

    The default generated script contains setup() and draw() functions. The setup() functions creates a canvas, and the draw() functions draws circles that follow the mouse. --options can be used to customize this script. See the reference, below.

    Build a static site

    p5 build SOURCES builds a static site into ./build.

    Run p5 build --help for a list of options.

    Two themes are supported, --theme grid and --theme split.

    Create a screenshot

    p5 screenshot my-sketch.js creates a screenshot named my-sketch.png in the current directory. It operates by running the sketch in a browser, saving the canvas, and then closing the browser page.

    You can also use p5 screenshot my-sketch.html for an HTML sketch; and p5 screenshot dir where dir names a single-sketch directory.

    Run p5 screenshot --help for a list of options. There are options to set the output filename, the number of the starting frame, the pixel density, the canvas dimensions, and the browser (Safari, Chrome, Firefox, or Edge).


    • Only the canvas is saved, not the HTML. Elements created with createButton(), createDiv() etc. are not captured in the screenshot.
    • The screenshot feature has not been tested with instance-mode sketches.

    Convert between JavaScript-only and HTML sketches

    p5 convert sketch.html converts an HTML sketch to a JavaScript-only sketch, by deleting the HTML file. It first inspects this file, to insure that the sketch contains only a single script file, and that all the information necessary to run the sketch is in the script.

    p5 convert sketch.js creates an HTML file that can be used to run the sketch.

    Command-Line Reference

    Run p5 --help to see a list of commands.

    Run p5 <command> --help to see command-line options for a particular command.

    p5 build [DIRECTORY]

    • p5 build creates an HTML index for a collection of sketches.
    • p5 build -o out places the index in the ./out directory. (The default is ./build.)

    p5 convert FILENAME --to FORMAT

    Converts between HTML and JavaScript-only sketches.

    • p5 convert FILENAME --to html creates an HTML file that uses the <script> tag to include the JavaScript sketch.
    • p5 convert FILENAME --to javascript removes an HTML file, leaving only the JavaScript file.

    Converting a JavaScript-only sketch is simple. An HTML file with the same base name is created, that includes the script, the p5.js source (from a CDN), and any inferred libraries. This will fail if the directory already contains a HTML file with this name.

    Converting an HTML sketch to a JavaScript-only sketch involves deleting the HTML file that includes the script. This potentially looses some information. Before the file is deleted, the following checks are made:

    • The HTML file includes only a single script file.
    • The libraries that the HTML file includes (via <script> tags) are the same as the libraries that will be inferred from the script file, based on the classes and functions that the script file uses and does not define.

    p5 create [NAME]

    Create a JavaScript-only sketch; or an HTML file and a JavaScript file.

    • p5 create – creates sketch.js
    • p5 create my-sketch.js – creates just the JavaScript file
    • p5 create my-sketch.html – creates my-sketch.html and my-sketch.js
    • p5 create my-sketch --type folder – creates a folder named my-sketch, that contains files index.html and sketch.js.

    p5 create --options comments,preload specifies a comma-separated set of template options. The options are:

    • comments – include comments (e.g. // put setup code here) inside the functions
    • preload – include an (empty) preload() function
    • windowResized – include a windowResized() function, that resizes the canvas when the window is resized
    • no-draw – omit the draw() function, in order to create a "static" sketch
    • no-examples – omit the example call inside of draw()

    p5 serve [filename]

    Runs a web server that knows about p5.js sketches.

    or the filename subdirectory of the current directory.

    p5 serve filename runs a sketch in the browser.

    • If filename is an HTML file (for example, index.html), this command serves that page.
    • If filename is a JavaScript file that contains a p5.js sketch (for example, sketch.js), the server serves a page that runs the sketch.
    • If filename is a directory, the browser displays a list of sketches and files in that directory.
    • If filename is not supplied, the browser displays sketches and files in the current directory. (This is the same as p5 serve ..)

    By default, the server runs on port 3000. You can open it in a browser by visiting http://localhost:3000. The p5 server --open will do this automatically.

    If another server is already running on port 3000, the server will choose another port.

    p5 screenshot [filename]

    Open the sketch in a browser, and save the canvas as an image.

    p5 tree [DIRECTORY]

    Display the contents of DIRECTORY, organized by sketch.

    $ p5 tree examples
    ├── 🎨circles (circles.js)
    ├── 🎨sketch
    │   ├── sketch.html
    │   ├── main.js
    │   └── helper.js
    ├── 🎨sketch-dir
    │   ├── index.html
    │   └── sketch.js
    ├── 🎨squares (squares.js)
    ├── 🎨syntax-error
    │   ├── index.html
    │   └── sketch.js
    ├── 📁collection
    │   ├── 🎨sketch 1 (sketch-1.js)
    │   ├── 🎨sketch 2 (sketch-2.js)
    │   └──
    ├── 📁libraries
    │   ├── 🎨dat.gui (dat.gui.js)
    │   ├── 🎨layers (layers.js)
    │   ├── 🎨posenet (posenet.js)
    │   ├── 🎨sound
    │   │   ├── sound.js
    │   │   └── doorbell.mp3
    │   ├── 🎨sound pulse (sound-pulse.js)
    │   ├── 🎨vector arguments (vector-arguments.js)
    │   └──

    This is similar to what the Sketch Explorer view in the Visual Studio Code extension displays.

    Additional commands

    Additional command-line tools are listed here.

    Implementation Notes

    The p5-analysis implementation notes describe sketch detection, automatic library inclusion, and other details of the implementation.


    • This code hasn't been tested on Windows.
    • Generated sketches require an internet connection the first time you run the server on a machine. Sketches load the p5.js and other libraries from a content delivery network (“CDN”). These libraries are cached (in ~/.cache/p5-server), so that reloading a page or running other sketches that use the same (or no) libraries does not require additional internet access.
    • This code hasn't been tested with instance-mode sketches.
    • Library inference hasn't been tested with sketches that are written as modules.
    • This is a development server, not a production server. It was not designed for security or performance.
    • See the p5-analysis implementation notes notes for limitations on the recognition of associated files.


    The server can be invoked programmatically. See the API Reference for installation instructions and reference documentation for this use.


    This project builds on these libraries and frameworks:

    • commander, chalk, and update-notifier for command-line-y stuff
    • esprima and node-html-parser for parsing JavaScript and HTML, respectively
    • expressjs for the web server
    • livereload for the live reload functionality
    • marked for converting Markdown to HTML
    • nunjucks and pug for template generation
    • The Semantic UI CSS framework
    • And of course [p5.js](https

    Other Work lists my other p5.js projects. These include tools, libraries, and examples and educational materials.

    Keeping in Touch

    Report bugs, features requests, and suggestions here, or message me on Twitter.

    Follow @osteele on Twitter for updates.


    MIT © by Oliver Steele


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