mensch

0.3.4 verified Sat Apr 25 auth: no javascript maintenance

A decent, non-validating CSS parser and stringifier. Current stable version is 0.3.4 (last release 2015-04-02, now in maintenance mode). Provides parse, stringify, and lex functions with support for comments and position tracking. Unlike validating parsers, mensch handles malformed CSS (mis-matched braces, missing semi-colons) without error. Differentiators: comments in AST, position info, and lenient parsing. Alternatives: PostCSS, css, csstree.

Common errors

error TypeError: mensch.parse is not a function ↓

cause Importing mensch incorrectly, e.g., import parse from 'mensch' instead of import mensch from 'mensch'.

fix

Use import mensch from 'mensch'; then mensch.parse().

error Cannot find module 'mensch' ↓

cause Package not installed or typo in package name.

fix

Run npm install mensch and ensure correct casing.

error Unexpected token ILLEGAL ↓

cause CSS contains modern syntax like CSS custom properties (var(--foo)) or nesting that mensch cannot parse.

fix

Switch to a modern parser like PostCSS.

Warnings

gotcha Mensch is a non-validating parser. It will not flag invalid CSS like misspelled property names or misplaced @import. ↓

fix Use a validating parser (e.g., PostCSS with stylelint) if validation is needed.

gotcha Comments within selectors, properties, or values are silently ignored. They do not appear in the AST even with {comments: true}. ↓

fix Keep comments only between rules or declarations.

deprecated The package has no new releases since 2015. It is effectively in maintenance mode; no updates for modern CSS features (e.g., custom properties, nesting). ↓

fix Consider using PostCSS or csstree for modern CSS parsing.

gotcha Global leak in v0.3.3 and earlier: the parser could leak variables into global scope. ↓

fix Update to v0.3.4 or later.

gotcha When using CommonJS require(), the default export is the whole module, not an object with methods. Use const mensch = require('mensch'); then mensch.parse(). ↓

fix Use const mensch = require('mensch'); or import * as mensch from 'mensch'.

Install

npm install mensch

yarn add mensch

pnpm add mensch

Imports

default
wrong
```
import { mensch } from 'mensch'
```
correct
```
import mensch from 'mensch'
```
Default import is the module object containing parse, stringify, lex.

parse

wrong

const parse = require('mensch').parse

correct

import { parse } from 'mensch'

Named import works in ESM; require also works in CJS.

stringify

wrong

import stringify from 'mensch'

correct

import { stringify } from 'mensch'

stringify is a named export, not default.

lex

wrong

const lex = require('mensch/lex')

correct

import { lex } from 'mensch'

lex is a member of the main module; no subpath.

Quickstart

Parse a CSS string with comments and positions, then stringify with indentation.

import mensch from 'mensch';

const css = 'p { color: black; }';
const ast = mensch.parse(css, { comments: true, position: true });
console.log(JSON.stringify(ast, null, 2));
const output = mensch.stringify(ast, { comments: true, indentation: '  ' });
console.log(output);