Parse error for multiline object props on React components

[mike-fam]

Initial checklist

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

Affected packages and versions

2.0.5

Link to runnable example

https://github.com/mike-fam/eslint-mdx-multiline-prop-error

Steps to reproduce

1. Create a new workspace with npm and install eslint with eslint-plugin-mdx
2. Eslint configuration:

{
   "overrides": [
   	{
   		"files": ["*.mdx"],
   		"extends": "plugin:mdx/recommended"
   	}
   ],
   "rules": {}
}

3. Create an mdx file with a react component with a multiline object prop e.g.

<button
   style={{
   	display: 'block'
   }}
>
   Test
</button>

4. Lint the file, note the error: Parsing error: Expected value to be truthy

Expected behavior

The file should pass linting without any problems, as this is valid mdx syntax.

Actual behavior

Linting produces the following error:
0:0 error Parsing error: Expected value to be truthy

Runtime

Node v16, Node v14

Package manager

yarn v1

OS

macOS

Build and bundle tools

webpack

[JounQin]

Thanks for reporting issue by using the template, I'm on a vocation these days, I'll check later soon.

[JounQin]

It seems related to tab, if I change the source codes with spaces there will be no issue:

<button
  style={{
    display: "block",
  }}
>
  Test
</button>

The assertion error is thrown at

eslint-mdx/packages/eslint-mdx/src/worker.ts

Line 491 in a1998c7

assert(text[attrValEnd] === '}')

I'll check how to fix this with tab

---

For text:

<button
	style={{
		display: 'block'
	}}
>
	Test
</button>

attrValue.data.estree.range is [16, 40], but it should be [16, 39] IMO, could it be an issue from micromark-extension-mdx-expression? @wooorm

I'll try to draft a simple reproduction for it.

[mike-fam]

Hi @JounQin, thanks for all your great work and investigating this. Is there any new update on this? For now, do you recommend replacing all the tabs in our stories with spaces or waiting for a new fix to be released?

[morganfeeney]

Hey @mike-fam did you manage to work around this one? I'm facing the same thing.

[Ayc0]

I investigated a bit this issue.

With the following code:

-   list

    <Components data={`
    `} />

I also have the error Parsing error: Expected value to be truthy

This crashes because of this line:

eslint-mdx/packages/eslint-mdx/src/worker.ts

Line 413 in 9331895

assert(text[attrValEnd] === '}')

.

When adding console.logs before and after attrValStart = prevCharOffset(attrValStart - 1); attrValEnd = nextCharOffset(attrValEnd);, here is what I have:

I think that the reason of the offset is because when writing <Component data={`\n `} />, acorn returns this node:

But the offsets start & end on the data attribute (32, 35) don't match the right start & end (end should have been 32, 38):

I'm not sure why the spaces are dropped in this estree (which comes from this processor

eslint-mdx/packages/eslint-mdx/src/worker.ts

Line 79 in 9331895

export const getRemarkProcessor = async (

).

[mike-fam]

Hi @JounQin @wooorm sorry for bothering you. Is there any update on this issue?

[remcohaszing]

If I’m correct, this repo is mainly maintained by @JounQin. However, we haven’t heard from him in a while.

Maybe we should create and pin a Looking for maintainers issue?

[JounQin]

As I and @Ayc0 discovered above, it is not an internal issue but due to acorn return incorrect location info, but I'm not sure if it comes from acorn itself or micromark-extension-mdx-expression instead because the location info is restored at

https://github.com/micromark/micromark-extension-mdx-expression/blob/88c175f9ac684efc9306e23642807657df71d6a6/packages/micromark-util-events-to-acorn/dev/index.js#L216

cc @wooorm

[mike-fam]

@JounQin @wooorm Would you guys mind creating an issue in either acorn or micromark-extension-mdx-expression, since I know little context to how the eslint-mdx plugin is implemented and how it uses those dependencies

[JounQin]

@wooorm Sorry to ping again, but I think we need your help here.

[wooorm]

I dunno where this problem is, I’d appreciate a reduced test case. If it isn’t in eslint-mdx, I’d appreciate a test case that doesn’t use eslint-mdx?

[JounQin]

Working on a minimal reproduction without eslint-mdx.

[JounQin]

@wooorm Please check https://github.com/JounQin/test/blob/mdx-tab/test.mjs#L29-L32

Besides, #435 (comment) could be another range issue not related to tab but list.

---

I tried acorn-jsx directly, there is no range issue:

/**
 * @typedef {import('estree').Program} Program
 * @typedef {import('estree-jsx').JSXElement} JSXElement
 * @typedef {import('estree-jsx').JSXAttribute} JSXAttribute
 */

const root =
  // @ts-expect-error
  /** @type {Program} */ (acorn.Parser.extend(acornJsx()).parse(contents, {
    ecmaVersion: 2020,
  }))
const statement = root.body[0]
if (typeof statement === 'object' && statement.type === 'ExpressionStatement') {
  const jsxElement = /** @type {JSXElement} */ (statement.expression)
  const attribute =
    /** @type {JSXAttribute} */ (jsxElement.openingElement.attributes[0])
  console.log(attribute.value)
}

Node {
  type: 'JSXExpressionContainer',
  start: 15,
  end: 21,
  expression: Node {
    type: 'TemplateLiteral',
    start: 16,
    end: 20,  // correct
    expressions: [],
    quasis: [ [Node] ]
  }
}

[wooorm]

@JounQin did you see my above commit?

[JounQin]

@wooorm Thanks! It seems working to me now. @mike-fam @morganfeeney @Ayc0 Can you help to confirm? You may need to delete your npm-lock.json or yarn.lock, etc to upgrade all related packages to confirm.

[Ayc0]

I think that this is working for me too! Thank you very much! 🎉

(with yarn 2+, you can run yarn up -R micromark-util-events-to-acorn to upgrade micromark-util-events-to-acorn in sub-dependencies without having to remove the whole yarn.lock)