Awesome
esast-util-from-estree
esast utility to transform from estree.
Contents
What is this?
This package applies some transforms to a cloned, given estree to make it compatible with unist. It:
- makes sure nodes are plain JSON
- adds unist positions
- normalizes
.bigint
- remove
attributes
,selfClosing
fromJSXOpeningFragment
- removes certain discouraged fields
When should I use this?
The transform applied by this utility is often optional: estrees can be used in most places where esast can be used, and vice versa. But, if you come from a unist background and want to deal with JavaScript, or want to use unist utilities with JavaScript, this helps a lot.
Install
This package is ESM only. In Node.js (version 16+), install with npm:
npm install esast-util-from-estree
In Deno with esm.sh
:
import {fromEstree} from 'https://esm.sh/esast-util-from-estree@2'
In browsers with esm.sh
:
<script type="module">
import {fromEstree} from 'https://esm.sh/esast-util-from-estree@2?bundle'
</script>
Use
import {parse} from 'acorn'
import {fromEstree} from './index.js'
// Make acorn support comments and positional info.
/** @type {Array<import('acorn').Comment>} */
const comments = []
/** @type {import('estree').Program} */
// @ts-expect-error: acorn looks like estree.
const estree = parse(
'export function x() { /* Something senseless */ console.log(/(?:)/ + 1n) }',
{
sourceType: 'module',
ecmaVersion: 'latest',
locations: true,
onComment: comments
}
)
estree.comments = comments
const esast = fromEstree(estree)
console.log(esast)
Yields:
{
type: 'Program',
body: [
{
type: 'ExportNamedDeclaration',
declaration: [Object],
specifiers: [],
source: null,
position: [Object]
}
],
sourceType: 'module',
comments: [
{
type: 'Block',
value: ' Something senseless ',
position: [Object]
}
],
position: {
start: {line: 1, column: 1, offset: 0},
end: {line: 1, column: 75, offset: 74}
}
}
API
This package exports the identifier fromEstree
.
There is no default export.
fromEstree(estree[, options])
Turn an estree into an esast.
Parameters
estree
(EstreeNode
) — estreeoptions
(Options
, optional) — configuration
Returns
Clean clone of estree
(UnistNode
).
Options
Configuration (TypeScript Type).
Fields
dirty
(boolean
, default:false
) — leave discouraged fields in the tree
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,
esast-util-from-estree@^2
, compatible with Node.js 16.
Contribute
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.