Registry / serialization / estree-util-to-js

estree-util-to-js

library2.0.0jsnpmunverified

estree-util-to-js is a focused utility designed to transform an ESTree (and ESast) syntax tree into a serialized JavaScript string. Its primary function is to convert in-memory syntax representations back into executable code, often after parsing and transformation within an AST processing pipeline. The current stable version is 2.0.0, which mandates Node.js 16 or higher and functions exclusively as an ESM-only package. While there isn't a fixed release cadence, updates typically occur as needed for features, bug fixes, or to align with evolving JavaScript standards, with major versions reserved for significant breaking changes like environment requirements or API shifts. This package is particularly valuable for projects within the unified ecosystem (unist, vfile) and integrates seamlessly with parsing tools like Acorn. It differentiates itself by providing a robust, extensible mechanism for code generation, including optional source map support and custom handlers for various AST nodes, offering a complementary utility to `esast-util-from-js` which performs the inverse operation.

serialization

npm install estree-util-to-js

github ↗package ↗

INSTALL

IMPORT

SIG · ESTREE-UTIL-TO-JS

estree-util-to-js

serializationjavascriptv2.0.0

Install

—

Import

—

Disk

—

Pass rate

0/ 6

Env Coverage0 / 6

glibc

18–22

musl

18–22

Install & Compatibility

Where this runs

tested against v? · npm install

Install × environment matrix

Each cell = how many times install + import succeeded across repeated harness runs. Partial = flaky.
glibc = Debian/Ubuntu slim · musl = Alpine Linux

musl

node 18–226 runs

build_error

glibc

node 18–226 runs

build_error

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

toJs

✓ import { toJs } from 'estree-util-to-js'

✗ const { toJs } = require('estree-util-to-js')

estree-util-to-js is an ESM-only package since v2.0.0. CommonJS `require` will not work.

jsx

✓ import { jsx } from 'estree-util-to-js'

✗ const { jsx } = require('estree-util-to-js')

The `jsx` export provides a map of handlers specifically for JSX nodes.

Map

✓ import type { Map } from 'estree-util-to-js'

This imports the TypeScript type definition for the raw source map object.

Demonstrates how to parse a JavaScript file using Acorn, then serialize its ESTree representation back into JavaScript code using `toJs`, including how to handle the `Result` object.

import fs from 'node:fs/promises'; import { parse } from 'acorn'; import { toJs } from 'estree-util-to-js'; async function serializeExample() { const fileContent = String(await fs.readFile('./input.js', 'utf8')); // Create a dummy file for the example await fs.writeFile('./input.js', 'export const greeting = "Hello, World!";', 'utf8'); const tree = parse(fileContent, { ecmaVersion: 2022, sourceType: 'module', locations: true // Required for source maps, though not used in simple output }); // @ts-expect-error: acorn's types can be complex with estree interop, but it works fine. const result = toJs(tree); console.log('Serialized JavaScript:\n', result.value); // console.log('Source Map (if generated):', result.map); // Clean up the dummy file await fs.unlink('./input.js'); } serializeExample().catch(console.error);

Debug

Known issues

breakingVersion 2.0.0 and above now requires Node.js 16 or newer. Older Node.js versions are not supported.

fix

Upgrade your Node.js environment to version 16 or higher.

affects: >=2.0.0

breakingThe package now strictly uses the `exports` field in its `package.json`. Direct imports to internal files (e.g., `estree-util-to-js/lib/index.js`) or reliance on CommonJS `require` patterns will fail.

fix

Migrate all imports to use standard ESM `import` statements and only import directly from the package name, e.g., `import { toJs } from 'estree-util-to-js'`.

affects: >=2.0.0

gotchaThis package is ESM-only. Attempting to use `require()` or run it in a CommonJS-only environment will result in errors.

fix

Ensure your project is configured for ESM (e.g., `"type": "module"` in `package.json` or using `.mjs` files) and use `import` statements for all modules.

affects: >=2.0.0

Errors

Common errors & fixes

require is not defined

Attempting to use CommonJS `require()` syntax to import `estree-util-to-js` in a module that is running as ECMAScript Module (ESM).

fix

Change `const { toJs } = require('estree-util-to-js')` to `import { toJs } from 'estree-util-to-js'`.

TypeError [ERR_UNKNOWN_FILE_EXTENSION]: Unknown file extension ".ts" for /path/to/node_modules/estree-util-to-js/index.ts

This error can occur if a bundler or environment is misconfigured to try to import TypeScript source files directly instead of compiled JavaScript, especially when `"type": "module"` is set.

fix

Ensure your build tools (e.g., TypeScript compiler, bundler) are correctly configured to resolve `estree-util-to-js` as a JavaScript module (ESM), respecting its `exports` field. Check `tsconfig.json` `moduleResolution` and bundler configurations.

Upgrade

Version history

2.0.0latest on npm

Audit

Dependencies

No dependency data recorded yet.

Agent activity

2 hits · last 30 days

node

Resources

githubhttps://github.com/syntax-tree/estree-util-to-js ↗

packagehttps://www.npmjs.com/package/estree-util-to-js ↗