invalid escape sequence in regular expression

[technobuddha]

quickjs compilation is failing with the error message invalid escape sequence in regular expression on the following code:

const re = /[\-]/u;

However, if the 'u' flag is omitted it compiles fine.

I found this problem using the very popular npm library ajv-formats (26 million DL/week)

[bnoordhuis]

I fixed that in 2023 in quickjs-ng/quickjs@f0ef9e1 although more as a side effect of a larger change. I think it should be possible to cherry-pick only the relevant bits though.

[benatkin]

It's more of a feature addition than a fix IMO

[technobuddha]

It's more of a feature addition than a fix IMO

I don't see how this is a "feature". It's clearly a bug. Node, and most browsers accept the regex syntax. The syntax is part of the regexp documentation.

[benatkin]

I understand it better now and yeah it isn't a feature. It's a bug that only shows up when the code has an unnecessarily escaped - in a unicode string. The spec and docs are very clear that it doesn't need to be escaped, so that code ought to be fixed in ajv.

[technobuddha]

@benatkin Exactly. I would consider this low-priority except for the fact that this is in several very popular npm packages including ajv.