Registry / http-networking / context-parser

context-parser

library2.0.1jsnpmunverified

context-parser is a robust and compact HTML5 context parser library designed to analyze web pages and report the execution context of each character, primarily for security purposes like preventing Cross-Site Scripting (XSS). The current stable version is 2.0.1. It differentiates itself by adhering strictly to the HTML5 WHATWG specification for accurate context determination, offering two distinct parser classes: `FastParser` for performance-critical scenarios and `Parser` for feature-rich analysis. The library is event-driven and focuses on the tokenization process to provide precise context reporting without unnecessary overhead, making it suitable for server-side HTML analysis. Its design emphasizes security, simplicity, and straightforward code for easier review and smaller footprint.

http-networking auth-security

npm install context-parser

github ↗package ↗

INSTALL

IMPORT

SIG · CONTEXT-PARSER

context-parser

http-networkingjavascriptv2.0.1

Install

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Import

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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.

Parser

✓ const { Parser } = require('context-parser');

✗ import { Parser } from 'context-parser';

The library primarily uses CommonJS `require` syntax as shown in official documentation. Direct ESM `import` may not be supported or requires specific Node.js configuration (e.g., `type: 'module'` in package.json) if the package doesn't ship ESM exports.

FastParser

✓ const { FastParser } = require('context-parser');

✗ import FastParser from 'context-parser';

Introduced in v2.0.0, `FastParser` is exported alongside `Parser` for performance-critical applications. Like `Parser`, it follows the CommonJS named export pattern.

contextualize

✓ parserInstance.contextualize(htmlString);

✗ contextualize(htmlString);

The `contextualize` method is an instance method of `Parser` (and likely `FastParser`) and must be called on an instantiated parser object, not as a standalone function. This API name was standardized in v2.0.0.

This quickstart demonstrates how to instantiate the `Parser` class, read an HTML file, and use the `contextualize` method to analyze its execution context in a Node.js environment.

const fs = require('fs'); const { Parser } = require('context-parser'); // Create a dummy HTML file for parsing const dummyHtmlContent = ` <!DOCTYPE html> <html> <head> <title>Test Page</title> <style>body { font-family: sans-serif; }</style> </head> <body> <h1>Hello World</h1> <script>console.log('Parsed!');</script>  </body> </html> `; const filePath = './test.html'; fs.writeFileSync(filePath, dummyHtmlContent, 'utf-8'); // Create the context parser const parser = new Parser(); // Read the HTML web page const data = fs.readFileSync(filePath, 'utf-8'); // Analyze the execution context console.log('Starting HTML context analysis...'); parser.contextualize(data); console.log('Analysis complete. Check parser events for details.'); // Clean up the dummy file fs.unlinkSync(filePath);

Debug

Known issues

breakingVersion 2.0.0 introduced significant breaking changes by separating the codebase into two distinct classes, `FastParser` and `Parser`, for different design objectives. The primary API for context analysis was standardized to `contextualize`.

fix

Review your code for direct usage of v1.x parsing methods. Migrate to instantiating either `Parser` or `FastParser` and calling the `contextualize()` method on the instance for context analysis.

affects: >=2.0.0

gotchaIn version 2.0.1, the initialization value for attribute values was changed from an empty string (`''`) to `null`. This might affect logic that expects attribute values to always be strings, even when not explicitly set.

fix

Ensure your code handles `null` values when accessing attribute values, especially in scenarios where attributes might be present but without an explicit value (e.g., boolean attributes). Add `null` checks where appropriate.

affects: >=2.0.1

Errors

Common errors & fixes

TypeError: context-parser is not a constructor

Attempting to `new require('context-parser')` or directly `new Parser()` without destructuring.

fix

Use object destructuring for CommonJS imports: `const { Parser } = require('context-parser');`

Error: Cannot find module 'context-parser'

The package is not installed or the Node.js module resolution path is incorrect.

fix

Run `npm install context-parser` in your project directory to install the package.

SyntaxError: Named export 'Parser' not found. The requested module 'context-parser' does not provide an export named 'Parser'

Attempting to use ES module `import { Parser } from 'context-parser'` syntax in a project that primarily uses CommonJS exports.

fix

If your project is CommonJS, switch to `const { Parser } = require('context-parser');`. If your project is ESM, verify if the package has a `type: 'module'` in its `package.json` or provides an `exports` field for ESM compatibility.

Upgrade

Version history

2.0.1latest on npm

Audit

Dependencies

No dependency data recorded yet.

Agent activity

19 hits · last 30 days

node

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Resources

githubhttps://github.com/yahoo/context-parser ↗

packagehttps://www.npmjs.com/package/context-parser ↗