acorn-hammerhead

library0.6.3jsnpmunverified

acorn-hammerhead is a specialized JavaScript parser derived from Acorn.js, specifically adapted for use within the TestCafe Hammerhead project. It is not intended as a general-purpose Acorn.js replacement, but rather provides a subset of Acorn's features tailored to Hammerhead's requirements. The current stable version is 0.6.3. Its release cadence appears irregular, driven by the needs and updates of the TestCafe Hammerhead project rather than independent feature development. Key differentiators include enhanced Unicode support and tighter integration with the Esotope library, alongside a deliberate reduction in the overall feature set compared to a full Acorn.js distribution, focusing only on the syntax elements pertinent to TestCafe's proxying and instrumentation logic. This package ships with TypeScript type definitions, enabling robust usage in TypeScript projects.

testing

npm install acorn-hammerhead

github ↗package ↗

INSTALL

IMPORT

SIG · ACORN-HAMMERHEAD

acorn-hammerhead

testingjavascriptv0.6.3

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.

parse

✓ import { parse } from 'acorn-hammerhead'

✗ const { parse } = require('acorn-hammerhead')

CommonJS `require` works, but ESM `import` is preferred for modern Node.js and TypeScript environments. The `parse` function is the primary entry point for parsing code.

Node

✓ import type { Node } from 'acorn-hammerhead'

Importing types like `Node` for Abstract Syntax Tree (AST) nodes should use `import type` for clarity and to avoid bundling type information in runtime code.

* as acorn

✓ import * as acorn from 'acorn-hammerhead'

✗ const acorn = require('acorn-hammerhead')

While `import * as` works, typically you'd destructure specific functions like `parse` directly. This pattern is less common for `acorn-hammerhead` as it exposes a limited API.

This quickstart demonstrates parsing a simple JavaScript code snippet using `acorn-hammerhead`'s `parse` function, logging the top-level AST nodes and details of the first node.

import { parse } from 'acorn-hammerhead'; const code = ` function greeting(name) { if (name?.length > 0) { console.log(`Hello, ${name}!`); } else { console.log('Hello, stranger!'); } } greeting('World'); greeting(); `; try { const ast = parse(code, { ecmaVersion: 2020, locations: true, sourceType: 'module' }); console.log('Successfully parsed AST top-level nodes:'); ast.body.forEach(node => console.log(`- ${node.type}`)); console.log('\nFirst node details:'); console.log(JSON.stringify(ast.body[0], null, 2)); } catch (error) { console.error('Parsing failed:', error); }

Debug

Known issues

gotchaacorn-hammerhead is a heavily customized and feature-limited fork of Acorn.js. It does not support all Acorn.js options or all ECMAScript features that a standard Acorn.js parser might. Consult the TestCafe Hammerhead codebase if unexpected parsing issues occur with advanced syntax.

fix

Ensure the code being parsed adheres to the subset of features supported by TestCafe Hammerhead. If you need full Acorn.js functionality, use the original `acorn` package instead.

affects: >=0.1.0

gotchaThe package's primary purpose is for TestCafe Hammerhead. Using it in contexts outside of TestCafe's internal proxying or transformation logic may lead to unexpected behavior or missing features compared to a general-purpose JavaScript parser.

fix

Only use `acorn-hammerhead` if you are specifically integrating with TestCafe's internal architecture or have confirmed its feature set meets your limited parsing needs. For general-purpose JavaScript parsing, use `acorn` or `@babel/parser`.

affects: >=0.1.0

breakingCodeQL vulnerabilities were fixed in v0.6.3. While not explicitly a breaking API change, upgrading is critical for security if your application processes untrusted code through this parser.

fix

Upgrade to `acorn-hammerhead@0.6.3` or newer to incorporate the security fixes. Review any custom parser logic you might have that relies on specific Acorn.js internal behaviors if upgrading from very old versions.

affects: <0.6.3

Errors

Common errors & fixes

SyntaxError: Unexpected token

The parsed code uses an ECMAScript feature or syntax that is not supported by the `acorn-hammerhead` version or the `ecmaVersion` option provided to the `parse` function.

fix

Ensure the `ecmaVersion` option passed to `parse` (e.g., `{ ecmaVersion: 2020 }`) matches or exceeds the features used in your code. If the feature is very recent or experimental, `acorn-hammerhead` might not support it at all due to its specialized nature.

TypeError: parse is not a function

Incorrect import statement or attempting to call a non-existent export. Common in mixed ESM/CJS environments or when destructuring incorrectly.

fix

Use `import { parse } from 'acorn-hammerhead';` for ESM, or `const { parse } = require('acorn-hammerhead');` for CommonJS. Verify that `parse` is indeed exported by the module in your environment.

Upgrade

Version history

0.6.3latest on npm

Audit

Dependencies

No dependency data recorded yet.

Agent activity

63 hits · last 30 days

node

OpenAI (training)

Resources

githubhttps://github.com/miherlosev/acorn-hammerhead ↗

packagehttps://www.npmjs.com/package/acorn-hammerhead ↗