@stackline/blanket

Maintained Blanket.js 1.2.3 compatibility fork with directive-safe coverage instrumentation.

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Current package version: 1.0.3

Why this package?

This is a maintained compatibility fork of the MIT-licensed [email protected] coverage instrumenter.

Version 1.0.0 fixed upstream issue #340: coverage counters no longer precede a function's directive prologue and accidentally disable strict mode. Program directives keep their order before coverage initialization; strictness does not leak between instrumented files. Ordinary string expressions, parenthesized strings, and escaped lookalikes do not become strict directives.

The implementation retains Blanket's instrumentation and coverage format. Its small MIT-licensed parser-walking and options-copying helpers are included internally, with attribution, and obsolete compatibility-shim dependencies are removed. Acorn is the single runtime dependency. The QUnit, Mocha, and Jasmine bundles, including their minified variants, are rebuilt from the same corrected source.

Compatibility

| Item | Value | | --- | --- | | Package | @stackline/[email protected] | | Supported Node.js | >=20 | | Module entry | src/index.js (CommonJS) | | Runtime dependencies | 1 direct dependency |

Browser bundles require ES5 array/object methods and a browser supported by the selected test framework. The default parser remains configured for ECMAScript 5; updating the parser does not make the legacy instrumenter support every newer syntax feature.

Installation

npm install --save-dev @stackline/blanket

The legacy Mocha require hook accepts the scoped name:

mocha --require @stackline/blanket

Usage

const blanket = require('@stackline/blanket')({ engineOnly: true });
const instrumented = blanket.instrumentSync({
  inputFile: "function example() { 'use strict'; return this; }",
  inputFileName: 'example.js'
});

Security

Instrumentation preserves directive prologues, including use strict. The default parser targets ECMAScript 5; newer parser dependencies do not imply support for every newer language feature.

API Surface

The full historical options and API reference are preserved in README.upstream.md. The compatibility notes above describe changes in the maintained package.

Local Development

Clone the repository and run the following commands from its root:

npm ci
npm run build
npm test

Tests cover strict-mode behavior, directive order, counters, callbacks, branch data, a real CommonJS require hook, and all six distributed browser instrumenters in VM browser contexts. Full browser-runner UI behavior and every historical framework version are not covered. The old Mocha html-cov reporter is a separate integration concern; this fork does not restore a reporter removed by Mocha.

Release Checklist

1. Update the package version, lockfile, generated version fields, and changelog together.
2. Run the development checks above and audit both npm audit and npm audit --omit=dev.
3. Use the GitHub publish workflow with its Prod environment to publish the exact CI tarball.
4. Verify public npm bytes, package identity, provenance, and the immutable GitHub release evidence.

License

MIT. Original copyright notices and upstream attribution are retained.

See UPSTREAM.md and THIRD_PARTY_NOTICES.md for the source basis and bundled helper attribution.

Credits and original authors

• Original project: blanket.
• Alex-Seville.
• Copyright (c) 2013 Alex Seville.
• Stackline maintenance: Alexandro Paixao Marques and Stackline contributors.

Original copyright, license notices and contributor acknowledgements remain part of this distribution. Stackline maintenance does not replace authorship of the original work.

Community and Links

• Stackline website
• GitHub projects
• npm packages
• Reddit community — r/Stackline
• Maintainer LinkedIn

Use this repository's issue tracker for reproducible bugs and feature requests. Join r/Stackline for examples, usage questions and release discussions.