[Markdown] Space removed before dollar sign

[BPScott]

In markdown a dollar sign seems to swallow all spaces before it when there is another one on the same line.

I think this is related to mathjax stuff and I think the solution is I need to escape all dollar signs but I wonder if there is some way that prettier can be smarter about how it treats these dollar signs pairings

//cc @ikatyang

Prettier 1.15.2
Playground link

Input:

$10 - $20
$10.00 and $40.00

Output:

$10 -$20
$10.00 and$40.00

Expected behavior:

As input

OR

\$10 - \$20
\$10.00 and \$40.00

[alexandernanberg]

Is Prettier meant to escape all $ from now on or just the ones in "math-syntax"?

For an example

Input

$5/month

Output

\$5/month

This still occurs on the preview of the #5485 PR

[ikatyang]

The math syntax is quite easy to be triggered, for example:

<!-- input -->
hello world $something __hi__ foo bar $baz
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^ this is parsed as math, which means
                                        its content will be preserved.
                                        `__hi__` is not considered a strong here.

<!-- output -->
hello world $something __hi__ foo bar $baz

So we escape all non-math dollar signs to reduce false positives (this rule is also applied to * and _):

<!-- input -->
hello world \$something __hi__ foo bar $baz
                        ^^^^^^ this is be parsed as strong

<!-- output -->
hello world \$something **hi** foo bar \$baz

If you saw a dollar sign that is not escaped, it's probably recognized as math syntax.

[alexandernanberg]

Ah I get it, thanks!