estree utility to turn JSX into function calls: <x />
-> h('x')
!
This package is a utility that takes an estree (JavaScript) syntax tree as input that contains embedded JSX nodes (elements, fragments) and turns them into function calls.
If you already have a tree and only need to compile JSX away, use this. If you have code, use something like SWC or esbuild instead.
This package is ESM only. In Node.js (version 16+), install with npm:
npm install estree-util-build-jsx
In Deno with esm.sh
:
import {buildJsx} from 'https://esm.sh/estree-util-build-jsx@3'
In browsers with esm.sh
:
<script type="module"> import {buildJsx} from 'https://esm.sh/estree-util-build-jsx@3?bundle' </script>
Say we have the following example.jsx
:
import x from 'xastscript' console.log( <album id={123}> <name>Born in the U.S.A.</name> <artist>Bruce Springsteen</artist> <releasedate date="1984-04-06">April 6, 1984</releasedate> </album> ) console.log( <> {1 + 1} <self-closing /> <x name key="value" key={expression} {...spread} /> </> )
…and next to it a module example.js
:
import fs from 'node:fs/promises' import jsx from 'acorn-jsx' import {fromJs} from 'esast-util-from-js' import {buildJsx} from 'estree-util-build-jsx' import {toJs} from 'estree-util-to-js' const doc = String(await fs.readFile('example.jsx')) const tree = fromJs(doc, {module: true, plugins: [jsx()]}) buildJsx(tree, {pragma: 'x', pragmaFrag: 'null'}) console.log(toJs(tree).value)
…now running node example.js
yields:
import x from "xastscript"; console.log(x("album", { id: 123 }, x("name", null, "Born in the U.S.A."), x("artist", null, "Bruce Springsteen"), x("releasedate", { date: "1984-04-06" }, "April 6, 1984"))); console.log(x(null, null, 1 + 1, x("self-closing"), x("x", Object.assign({ name: true, key: "value", key: expression }, spread))));
This package exports the identifier buildJsx
. There is no default export.
buildJsx(tree[, options])
Turn JSX in tree
into function calls: <x />
-> h('x')
!
In almost all cases, this utility is the same as the Babel plugin, except that they work on slightly different syntax trees.
Some differences:
this
is not a component: <this>
-> h('this')
, not h(this)
<a:b c:d>
-> h('a:b', {'c:d': true})
, which throws by default in Babel or can be turned on with throwIfNamespace
useSpread
, useBuiltIns
, or filter
optionsNothing (undefined
).
Configuration (TypeScript type).
👉 Note: you can also configure
runtime
,importSource
,pragma
, andpragmaFrag
from within files through comments.
Choose the runtime (Runtime
, default: 'classic'
).
Comment form: @jsxRuntime theRuntime
.
Place to import jsx
, jsxs
, jsxDEV
, and Fragment
from, when the effective runtime is automatic (string
, default: 'react'
).
Comment form: @jsxImportSource theSource
.
👉 Note:
/jsx-runtime
or/jsx-dev-runtime
is appended to this provided source. In CJS, that can resolve to a file (as intheSource/jsx-runtime.js
), but for ESM an export map needs to be set up to point to files:// … "exports": { // … "./jsx-runtime": "./path/to/jsx-runtime.js", "./jsx-dev-runtime": "./path/to/jsx-runtime.js" // …
Identifier or member expression to call when the effective runtime is classic (string
, default: 'React.createElement'
).
Comment form: @jsx identifier
.
Identifier or member expression to use as a symbol for fragments when the effective runtime is classic (string
, default: 'React.Fragment'
).
Comment form: @jsxFrag identifier
.
When in the automatic runtime, whether to import theSource/jsx-dev-runtime.js
, use jsxDEV
, and pass location info when available (boolean
, default: false
).
This helps debugging but adds a lot of code that you don’t want in production.
File path to the original source file (string
, example: 'path/to/file.js'
). Passed in location info to jsxDEV
when using the automatic runtime with development: true
.
How to transform JSX (TypeScript type).
type Runtime = 'automatic' | 'classic'
To support configuration from comments in Acorn, those comments have to be in the program. This is done by espree
but not automatically by acorn
:
import {Parser} from 'acorn' import jsx from 'acorn-jsx' const doc = '' // To do: get `doc` somehow. const comments = [] const tree = Parser.extend(jsx()).parse(doc, {onComment: comments}) tree.comments = comments
This package is fully typed with TypeScript. It exports the additional type Options
and Runtime
.
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, estree-util-build-jsx@^3
, compatible with Node.js 16.
syntax-tree/hast-util-to-estree
— turn hast (HTML) to estree JSXcoderaiser/estree-to-babel
— turn estree to Babel treesThis package is safe.
See contributing.md
in syntax-tree/.github
for ways to get started. See support.md
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.
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