HTML comments are not considered comments

[NotWearingPants]

In JavaScript, HTML comments are a valid replacement for single line comments.
They are considered comments in Node.js, inline script tags, external js file, etc.

<!-- No comment.
// Comment.

Even GitHub doesn't seem to understand this syntax 🤔

Your grammar does not seem to support them, and mistakes them as a syntax error.

Link to the relevant part of the spec

In the spec this syntax appears under additional syntax for web browsers, yet you do support the other additional syntax in that section, such as legacy octal numeric literals and octal string escapes, but not HTML comments.

[NotWearingPants]

This issue was spotted by @RadiatedMonkey in microsoft/vscode#82612

[NotWearingPants]

From what I understand from the spec:

an HTML open comment (<!--) is interchangable with a JS line comment (//):

code() // comment
moreCode() <!-- more comment

and an HTML close comment (-->) is also similar to a JS line comment, but only if there is nothing before it in the line other than whitespace or multiline comments:

--> line comment

    --> whitespace

/* multiline comment */ --> more comment

/*
   the multiline comment
   doesn't have to be opened
in the */ --> same line

/* many */ /* are */ --> allowed