🃏 Jesta

Stencila plugin for executable documents using JavaScript

✨ Features

Implements compile, build and execute methods for CodeChunk and CodeExpression nodes with Javascript as their programmingLanguage.
Implements vars, get, set and delete methods for managing variables in Node.js.
Implements funcs, and call methods for using functions defined in Node.js.
Implements decode and encode methods for document format json.
Implements select for query language simplepath.
Implements read and write for protocols file://, http:// (with RFC 7234 compliant caching), and stdio://.
Implements the validate method to validate documents against Stencila JSON Schema. By default, coerces inputs to meet the schema (e.g. dropping unknown properties, parsing dates) but this can be turned off with --force=false.
A base for other plugins written in Javascript or Typescript (implements manifest and serve methods required for integration with Stencila CLI and Desktop)
A simple command line interface, including interactive modes, for running and testing plugins.

🏗️ Roadmap

📦 Install

Via `stencila`

This is the default plugin for using Javascript with Stencila. Install it using the Stencila CLI,

stencila plugins install javascript

Or using the name of this repo directly,

stencila install jesta

Via `npm`

If you have Node.js and NPM installed,

npm install --global @stencila/jesta

Via `docker`

A Docker image is built for each release,

docker pull stencila/jesta

🚀 Use

Most of the time you won't use Jesta directly (it's more likely that you will use one of the plugins extended from it, or use it via the Stencila CLI).

But if you do want to run Jesta standalone, for example to execute a document containing Javascript code,

jesta execute document.json

Or, if you are using the Docker image,

docker run -it --rm -v$PWD:/work -w/work stencila/jesta execute document.json

💪 Extend

Jesta is designed to be extended so that you can create your own Stencila plugins using Javascript or Typescript.

Getting started

Initialize your package and add Jesta as a dependency:

npm init
npm install @stencila/jesta

Override one or more method

Override any of Jesta's methods e.g. compile and in your index.ts or index.js, call Jesta's cli function e.g.

import { Jesta } from '@stencila/jesta'
import { compile } from './compile'

export class MyPlugin extends Jesta {
  compile = compile
}

if (require.main === module) new MyPlugin().cli()

Write a `codemeta.json` file

The codemeta.json file contains metadata (based on the Codemeta and schema.org standards) about your plugin including how it can be installed and it's capabilities. This metadata is used by Stencila to determine how it should install your plugin, how to run it, and what functions should be delegated to it.

A good place to start is by copying Jesta's codemeta.json file and modifying it. At a minimum, the codemeta.json file should include a name, description, a installUrl array containing the NPM URL of the package, and a featureList array.

{
  "name": "myplugin",
  "description": "My awesome plugin",
  "installUrl": [
    "https://www.npmjs.com/package/myplugin",
  ],
  "featureList": [
    ...
  ]
}

Publish standalone binaries

Not everyone has Node.js installed. To make your plugin available to as many possible users as possible we encourage you to create standalone binaries for major operating systems.

This repo provides an example of how to create standalone binaries for Linux, MacOS and Windows using pkg. These binaries are published for each release with a target triplet name that is suitable for download by Stencila. Check out the build.sh script and the pkg property in the package.json to see how to reuse this approach for your own plugin.

Add the binaries as assets to each release (see how we do this automatically using semantic-release) and add the GitHub releases URL to installUrl so that Stencila knows that standalone binaries are an installation option:

  "installUrl": [
    ...
    "https://github.com/me/myplugin/releases"
  ]

Publish a Docker image

Some users may prefer to use your plugin as a Docker image.

This repo contains a Dockerfile that shows how you can create a Docker image for your plugin based on the Linux binary. Once it is published add the Docker Hub URL to installUrl so that Stencila knows that is an installation option:

  "installUrl": [
    ...
    "https://hub.docker.com/r/me/myplugin"
  ]

💬 Tip: Stencila will attempt to install a plugin based on the order of URLs in installUrl. So, for example, if it's best that your users use a Docker image, put it first and that method will be used, if possible, and if the user hasn't specified a installation preference.

🛠️ Develop

Get started by cloning this repository, installing dependencies and running the command line interface:

git clone git@github.com:stencila/jesta
cd jesta
npm install
npm start

Please run the formatting, linting and testing scripts when contributing code e.g.

npm run format
npm run lint
npm run test::watch

Alternatively, use make if you prefer,

make format lint test

There are also some test fixtures that you can try the CLI out on e.g.

npm start -- compile+build+execute tests/fixtures/one/index.json

🙏 Acknowledgements

The read method uses got, keyv and content-type to enable cached reads of URLs and determine the format of the returned content.
The validate method uses Ajv, "the fastest JSON Schema validator for Node.js and browser", to validate and coerce JSON documents against our schema.
The compile method relies on Acorn, a "tiny, fast JavaScript parser, written completely in JavaScript", to determine the imports, declares, uses etc properties of CodeChunk and CodeExpression nodes in documents.
The command line interface is implemented using minimist.

stencila/jesta