recma-parse

recma plugin to add support for parsing JavaScript.

Contents

• What is this?
• When should I use this?
• Install
• Use
• API
  • unified().use(recmaParse[, options])
  • Options
• Syntax
• Syntax tree
• Types
• Compatibility
• Security
• Contribute
• License

What is this?

This package is a unified (recma) plugin that defines how to take JavaScript as input and turn it into a syntax tree. When it’s used, JavaScript can be parsed and other recma plugins can be used.

See the monorepo readme for info on what the recma ecosystem is.

When should I use this?

This plugin adds support to unified for parsing JavaScript. If you also need to serialize JavaScript, you can alternatively use recma, which combines unified, this plugin, and recma-stringify.

If you don’t use plugins and want to access the syntax tree, you can directly use esast-util-from-js, which is used inside this plugin. recma focusses on making it easier to transform code by abstracting such internals away.

Install

This package is ESM only. In Node.js (version 16+), install with npm:

npm install recma-parse

In Deno with esm.sh:

import recmaParse from 'https://esm.sh/recma-parse@1'

In browsers with esm.sh:

<script type="module">
  import recmaParse from 'https://esm.sh/recma-parse@1?bundle'
</script>

Use

Say we have the following module example.js:

import recmaBuildJsx from 'recma-build-jsx'
import recmaJsx from 'recma-jsx'
import recmaParse from 'recma-parse'
import recmaStringify from 'recma-stringify'
import {unified} from 'unified'

const file = await unified()
  .use(recmaParse)
  .use(recmaJsx)
  .use(recmaBuildJsx)
  .use(recmaStringify)
  .process('console.log(<em>Hi!</em>)')

console.log(String(file))

…running that with node example.js yields:

console.log(React.createElement("em", null, "Hi!"));

API

This package exports no identifiers. The default export is recmaParse.

unified().use(recmaParse[, options])

Plugin to add support for parsing from JavaScript.

Parameters

• options (Options, optional) — configuration

Returns

Nothing (undefined).

Options

Configuration (TypeScript type).

Same as Options from esast-util-from-js.

Syntax

JS is parsed according to ECMA-262, which is also followed by all browsers and engines such as Node.js.

Syntax tree

The syntax tree format used in recma is esast and estree.

Types

This package is fully typed with TypeScript. It exports the additional type Options.

Compatibility

Projects maintained by the unified collective are compatible with maintained versions of Node.js.

When we cut a new major release, we drop support for unmaintained versions of Node. This means we try to keep the current release line, recma-parse@1, compatible with Node.js 16.

Security

As recma works on JS and evaluating JS is unsafe, use of recma can also be unsafe. Do not evaluate unsafe code.

Use of recma plugins could also open you up to other attacks. Carefully assess each plugin and the risks involved in using them.

For info on how to submit a report, see our security policy.

Contribute

See § Contribute on our site for ways to get started. See § Support for ways to get help.

This project has a code of conduct. By interacting with this repository, organization, or community you agree to abide by its terms.

License

MIT © Titus Wormer