Zero-width-character-escaped double-asterisk sequence is not ignored, whereas zero-width-character-escaped single asterisk is

[haqer1]

E.g.:

***Essai** 57* :

Ligne 2.

2 ​* 3 ​* 4 = 24

Some langs treat this as equivalent of ^: 2 ​*​* 3 ​*​* 4 = 2,417851639×10²⁴

37e ***chose* *très* importante**.

Just wondering if this is considered an issue or not (and if so why it is OK to be different for single vs. double asterisk).
Logged the same at markdown-it, which seems to behave the same way in this regard: markdown-it/markdown-it#607

[haqer1]

To clarify, double asterisk in the example above disappears in HTML rendered.

[jgm]

If I understand correctly, you a zero-width character between the two asterisks.

• Which character is it?
• Why do you have it there?

[haqer1]

If I understand correctly, you a zero-width character between the two asterisks.

In front of each of the two.

* Which character is it?

E.g.:

var s110="***Essai** 57* :\n Ligne 2.\n2 ​* 3 ​* 4 = 24\nSome langs treat this as equivalent of ^: 2 "
 + String.fromCharCode(8203)+ '*' + String.fromCharCode(8203)+ "*" + " 3 " + String.fromCharCode(8203)+ "*" 
   + String.fromCharCode(8203)+ "* 4 = 4096\nUne ***chose* *très* importante**.";

* Why do you have it there?

I was playing with escaping asterisk.

P.S. Escaping seems to be the weak link in Markdown, which could make one question whether it's worth using it when only a limited set of HTML is involved.

[jgm]

The behavior of commonmark.js accords with the spec. Zero-width space is not "unicode whitespace" according to the spec (because it's not in the Zs category). Hence * + ZERO_WIDTH_SPACE + * yields an emphasized ZERO_WIDTH_SPACE rather than a double asterisk.

[haqer1]

Actually, it would be more appropriate to compare zero-width-space character with \ character: both seem to escape the following character, but the former seems to not work on when applied to each in a sequence of 2 characters as mentioned in the OP (while it escapes 1 asterisk OK), for instance.

P.S. These kinds of quirks make me question presently whether i should use MD as it is in a web app. Although, it's definitely attractive for keeping notes (or for a project description file as on github), for instance.

[puzrin]

@haqer1 if you need quick hack - just replace ZWS with \ on input, to get behaviour you wish.