parserlib

library0.1.1jsnpmunverified

ParserLib is a CSS3 SAX-inspired parser written in JavaScript, designed for event-driven parsing of CSS stylesheets. It supports standard CSS syntax and offers a degree of validation for property names and values, though it is not exhaustive. The library is currently at version 1.1.1, with its most recent update focused on build file regeneration and minor CSS3 feature additions like `turn` units and nested media query support. Unlike AST-based parsers, ParserLib emits events during the parsing process rather than constructing a syntax tree, requiring developers to implement listeners for desired functionalities. It is built to operate in various JavaScript environments, including Node.js, Rhino, and directly in HTML pages, making it versatile for different project setups.

serialization data

npm install parserlib

github ↗package ↗

INSTALL

IMPORT

SIG · PARSERLIB

parserlib

serializationjavascriptv0.1.1

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.

parserlib

✓ const parserlib = require('parserlib');

✗ import parserlib from 'parserlib';

The library primarily supports CommonJS 'require' syntax. Direct ESM 'import' is not natively supported without a transpilation step.

parserlib.css.Parser

✓ const { Parser } = require('parserlib').css;

✗ import { Parser } from 'parserlib/css';

Access the Parser class through the `css` namespace of the main `parserlib` object. ESM imports are not directly supported.

parser.addListener

✓ parser.addListener('property', (event) => console.log(event.property.text));

ParserLib is SAX-inspired and event-driven; there is no AST. Interact with the parsed CSS by adding listeners for specific events like 'property', 'rule', etc.

Demonstrates initializing the CSS parser with 'starHack' and 'underscoreHack' options and parsing a sample CSS string. It highlights the event-driven nature where no AST is returned directly.

Debug

Known issues

breakingMajor version `1.0.0` was released without explicit breaking change documentation. Users upgrading from `0.x` versions should anticipate potential API changes and thoroughly test their applications.

fix

Review project-specific changelogs or GitHub releases for `v1.0.0` if available, and adapt code to the updated API. Implement comprehensive tests to identify regressions.

affects: >=1.0.0

gotchaParserLib is a SAX-inspired, event-driven parser and *does not* construct or return an Abstract Syntax Tree (AST). Developers must attach event listeners to process CSS rules and properties incrementally.

fix

Instead of expecting a return value with a parse tree, register event listeners for specific CSS constructs (e.g., `startstylesheet`, `property`, `rule`) to capture and process information as it's parsed. Example: `parser.addListener('property', (event) => { /* ... */ });`

affects: All versions

gotchaThe parser's validation capabilities are not exhaustive; it is 'not guaranteed to thoroughly validate all possible CSS properties.'

fix

For strict CSS validation requirements, integrate additional dedicated CSS validation tools alongside ParserLib. Do not rely solely on ParserLib for comprehensive syntax or semantic checks.

affects: All versions

gotchaThe library predominantly supports CommonJS modules (`require()`). Direct ECMAScript Module (`import`) syntax is not natively supported without transpilation or a bundler.

fix

In Node.js environments, use `const parserlib = require('parserlib');`. For browser use, ensure the `parserlib.js` script is loaded via a `<script>` tag. For modern ESM projects, a bundler or manual CommonJS-to-ESM conversion might be necessary.

affects: All versions

gotchaParsing large CSS files directly in a browser environment can lead to unresponsiveness, as indicated in the documentation.

fix

For client-side parsing of substantial CSS, consider processing in Web Workers to offload the main thread, or pre-process CSS on the server-side.

affects: All versions (browser environments)

Errors

Common errors & fixes

Syntax Error: Expected <token> at line X, column Y

The input CSS string contains a malformed syntax that the parser cannot recover from.

fix

Examine the CSS content at the reported line and column, and correct the syntax. Consider enabling `strict: false` option during parser initialization for basic error recovery, although it may not resolve all issues.

TypeError: parserlib.css.Parser is not a constructor

The 'parserlib' module or its 'css' property was not correctly loaded or is undefined.

fix

Ensure `require('parserlib')` successfully loads the module. Verify that the script loading order is correct in browser environments if using `<script>` tags, or that the bundler configuration is correct for CommonJS modules.

ReferenceError: require is not defined (when using 'require' in browser)

Attempting to use Node.js-specific `require` syntax in a browser environment without a CommonJS module loader/bundler.

fix

For browser usage, include `parserlib.js` via a `<script>` tag. If using a module system in the browser, ensure your bundler (e.g., Webpack, Rollup) is configured to handle CommonJS modules.

Upgrade

Version history

0.1.1latest on npm

Audit

Dependencies

No dependency data recorded yet.

Agent activity

2 hits · last 30 days

node

Resources

githubhttps://github.com/CSSLint/parser-lib ↗

packagehttps://www.npmjs.com/package/parserlib ↗