rc.4 and rc.5 crash on a script that works in rc.3

[ljharb]

To repro:

1. Clone https://github.com/ljharb/es-abstract/ and npm install
2. npm install cheerio@1.0.0-rc.3
3. node operations/getOps 2020, observe it completes
4. npm install cheerio@1.0.0-rc.4 (or 5)
5. node operations/getOps 2020, observe it crashes with:

$PWD/node_modules/cheerio/lib/api/traversing.js:30
    return newElems.concat(elem.children.filter(isTag));
                                         ^

TypeError: Cannot read property 'filter' of undefined
    at $PWD/node_modules/cheerio/lib/api/traversing.js:30:42
    at Array.reduce (<anonymous>)
    at module.exports.exports.find ($PWD/node_modules/cheerio/lib/api/traversing.js:29:30)
    at Object.<anonymous> ($PWD/operations/getOps.js:29:43)

Since this is a dev-only script, I only need to use it in node 14 or higher.

[5saviahv]

yes, it seems like in find function does not have condition determining if collection element is text node.

[5saviahv]

Cheerio should be able handle it, but I would suggest change code so document will be parsed with load function

...
const root = $.load(specHTML);

let aOps = root('[aoid]');

if (aOps.length === 0) {
	aOps = root('p:contains(" abstract operation ")').closest('section').add(root('#sec-reference-specification-type > section'));
}
...

[ljharb]

What’s the advantage of that?

[5saviahv]

This is how Cheerio is meant to work. Load document and then make requests against it.

Current setup also should work, but it is clearly not enough tested.

[ljharb]

I expect cheerio to work just like jquery works :-) but thanks, appreciate the workaround.

[fb55]

Thanks for the report! Quite unfortunate that this happened & thanks @5saviahv for stepping in!

[ljharb]

Thanks, with this and hopefully #1585 fixed, i'll be able to update to rc6 (or a regular v1) everywhere ;-)

[lsbyerley]

I have come across this issue as well after upgrading from 1.0.0-rc.3 to 1.0.0-rc.5 .. however, i'm not exactly sure what I should be doing differently. My function is below and the error is generated at the .find() line

  const myFunc = async () => {
    const url = 'https://www.myurl.com';
    const theRes = await axios.get(url);

    const $ = cheerio.load(theRes.data, { normalizeWhitespace: true });
    const theDiv = $('#some_div_id');
    let rawHtml = theDiv.html();
    rawHtml = rawHtml.replace('<!--', '');
    rawHtml = rawHtml.replace('-->', '');

    const theDomNodes = cheerio.parseHTML(rawHtml);
    const theRows = $(theDomNodes).find('table#some_table_id tbody tr');

  ...
}

[fb55]

Hi @lsbyerley, what error are you seeing?

[lsbyerley]

@fb55 the same one posted by the OP..

TypeError: Cannot read property 'filter' of undefined
at /sandbox/node_modules/cheerio/lib/api/traversing.js:30:42

[ljharb]

The fix isn’t released yet, afaict

[lsbyerley]

alright no problem, i can downgrade until the release