Parse errors occur on formulas with `remark-math`

[r4ai]

Initial checklist

• I read the support docs
• I read the contributing guide
• I agree to follow the code of conduct
• I searched issues and discussions and couldn’t find anything (or linked relevant results below)

Affected package

eslint-plugin-mdx@3.4.1

Steps to reproduce

A minimal and reproducible repository is available here:

https://github.com/r4ai/eslint-plugin-mdx-math-issue

Actual behavior

I added remark-math to the plugins array in .remarkrc.js as shown below, but the parse error still persists.

.remarkrc.js:

import remarkPresetLintConsistent from "remark-preset-lint-consistent";
import remarkPresetLintRecommended from "remark-preset-lint-recommended";
import remarkMath from "remark-math";
import remarkPresetLintMarkdownStyleGuide from "remark-preset-lint-markdown-style-guide";
import remarkPresetPrettier from "remark-preset-prettier";

export default {
  plugins: [
    remarkMath,
    remarkPresetLintConsistent,
    remarkPresetLintRecommended,
    remarkPresetLintMarkdownStyleGuide,
    remarkPresetPrettier,
  ],
};

math.mdx:

$$
\forall \epsilon > 0, \exists \delta > 0 \text{ s.t. } |x - a| < \delta \Rightarrow |f(x) - b| < \epsilon
$$

$ bun run eslint .

/home/r4ai/src/repos/github.com/r4ai/eslint-plugin-mdx-math/src/math.mdx
  0:54  error  Preprocessing error: Could not parse expression with acorn

✖ 1 problem (1 error, 0 warnings)

Expected behavior

Parse normally

Runtime

node@22.15.0

bun@1.2.11

Package manager

bun@1.2.11

Operating system

Ubuntu 24.04.2 LTS

Build and bundle tools

No response

[PaulRBerg]

I am also getting a no-unused-expressions error for this MDX:

the aggregate amount would be $100m*10^{18}$

Specifically, for the {18} part.

[JounQin]

Sorry I didn't notice this issue, I'll take a look soon later.

[JounQin]

Please try https://github.com/mdx-js/eslint-mdx/releases/tag/eslint-plugin-mdx%403.5.0.

[PaulRBerg]

I am still getting an error even on v3.5.0 for my {18} exponent:

72:88  error  Expected an assignment or function call and instead saw an expression  no-unused-expressions

[JounQin]

@PaulRBerg Please raise a new issue with minimal but runnable reproduction if you've enabled remark-math in your remarkrc. I can't reproduce it with https://github.com/r4ai/eslint-plugin-mdx-math-issue and v3.5.0.