mhchemparser

library4.2.1jsnpmunverified

mhchemParser is a JavaScript/TypeScript library designed to convert chemical equations and physical units written in the mhchem syntax into standard LaTeX syntax. This conversion is crucial for rendering chemical notation accurately in environments that support LaTeX, such as MathJax and KaTeX. The current stable version is 4.2.1. It serves as a foundational parser, allowing developers to process mhchem input directly before feeding it into a LaTeX rendering engine. The library is actively maintained and differentiates itself by providing a robust, standalone parsing capability specifically for mhchem syntax, rather than being an integrated component of a larger rendering system. Its primary utility is for downstream software integration, enabling flexible handling of chemical typesetting.

serialization

npm install mhchemparser

github ↗package ↗

INSTALL

IMPORT

SIG · MHCHEMPARSER

mhchemparser

serializationjavascriptv4.2.1

Install

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Import

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Disk

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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.

mhchemParser

✓ import { mhchemParser } from 'mhchemparser';

✗ import mhchemParser from 'mhchemparser'; // Or import { toTex } from 'mhchemparser';

The library exports a class named `mhchemParser` with a static method `toTex` for parsing. It is not a default export, nor is `toTex` a direct named export.

mhchemParser.toTex

✓ import { mhchemParser } from 'mhchemparser'; mhchemParser.toTex("CO2", "ce");

✗ import { toTex } from 'mhchemparser'; toTex("CO2", "ce");

`toTex` is a static method of the `mhchemParser` class and must be called via the class name.

mhchemParser (CommonJS)

✓ const { mhchemParser } = require('mhchemparser');

✗ const mhchemParser = require('mhchemparser'); const toTex = require('mhchemparser').toTex;

For CommonJS environments, the `mhchemParser` class should be destructured from the require call.

Demonstrates how to import the mhchemParser class and use its static 'toTex' method for converting mhchem syntax in chemical equations, physical units, and embedded TeX strings into LaTeX.

import { mhchemParser } from 'mhchemparser'; // Parse a chemical equation const equationInput = "CO2 + C -> 2 CO"; const equationOutput = mhchemParser.toTex(equationInput, "ce"); console.log(`Input: \\ce{${equationInput}}\nOutput: ${equationOutput}`); // Expected output: Input: \ce{CO2 + C -> 2 CO} // Output: {\mathrm{CO}{\vphantom{A}}_{\smash[t]{2}} {}+{} \mathrm{C} {}\mathrel{\longrightarrow}{} 2\,\mathrm{CO}} // Parse a physical unit const unitInput = "123 kJ*mol-1"; const unitOutput = mhchemParser.toTex(unitInput, "pu"); console.log(`Input: \\pu{${unitInput}}\nOutput: ${unitOutput}`); // Expected output: Input: \pu{123 kJ*mol-1} // Output: 123\,\mathrm{kJ}{\cdot}\mathrm{mol}^{-1} // Parse a TeX string containing mhchem commands const texInput = "m_{\\ce{H2O}}"; const texOutput = mhchemParser.toTex(texInput, "tex"); console.log(`Input: ${texInput}\nOutput: ${texOutput}`); // Expected output: Input: m_{\ce{H2O}} // Output: m_{\mathrm{H}_{2}\mathrm{O}}}

Debug

Known issues

gotchaProviding malformed or syntactically incorrect mhchem input may lead to unexpected or incomplete LaTeX output, or internal errors depending on the severity of the input issue. While the parser aims for robustness, it's not a full semantic validator.

fix

Always consult the mhchem manual (mhchem.github.io/MathJax-mhchem/) for correct syntax. Validate user input before passing it to `mhchemParser.toTex` to ensure it conforms to expected mhchem patterns.

affects: >=1.0.0

gotchaThe `mhchemParser` class's `toTex` method expects a specific `type` argument ('ce', 'pu', or 'tex'). Providing an incorrect or unrecognized type will result in incorrect parsing behavior or errors.

fix

Ensure the second argument to `mhchemParser.toTex` is one of the supported strings: 'ce' for chemical equations, 'pu' for physical units, or 'tex' for general TeX strings containing mhchem commands.

affects: >=1.0.0

breakingWhile no explicit major breaking changes were detailed in the provided README excerpt, developers should always review the official changelog or GitHub releases when updating between major versions to identify potential API changes or behavior shifts.

fix

Before upgrading to a new major version, check the project's GitHub releases page and the `MathJax-mhchem` manual for any migration guides or breaking changes that might affect your integration.

affects: >=4.0.0

Errors

Common errors & fixes

TypeError: mhchemParser.toTex is not a function

Incorrect import of the `mhchemParser` class, leading to `mhchemParser` being `undefined` or not the expected class object.

fix

Ensure you are using `import { mhchemParser } from 'mhchemparser';` (ESM) or `const { mhchemParser } = require('mhchemparser');` (CommonJS). `toTex` is a static method of the exported class.

ReferenceError: mhchemParser is not defined

The `mhchemParser` class was not imported or destructured correctly, or the import statement was entirely missed.

fix

Add the correct import statement at the top of your file: `import { mhchemParser } from 'mhchemparser';` (ESM) or `const { mhchemParser } = require('mhchemparser');` (CommonJS).

MathJax or KaTeX renders raw `\ce{...}` or `\pu{...}` commands

The mhchem parser was not invoked, or its output was not correctly passed to the LaTeX rendering engine. The `\ce` and `\pu` commands are specific to mhchem syntax, not raw LaTeX.

fix

Ensure that you call `mhchemParser.toTex(yourInput, 'ce')` or `mhchemParser.toTex(yourInput, 'pu')` on your input string *before* passing it to MathJax or KaTeX for rendering. The output of `toTex` is standard LaTeX.

Upgrade

Version history

4.2.1latest on npm

Audit

Dependencies

No dependency data recorded yet.

Agent activity

12 hits · last 30 days

node

Resources

githubhttps://github.com/mhchem/mhchemParser ↗

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