How to create a showdown.js markdown extension

Question

Using the following code, I get working output:

Answer 1

In your last block you have a comma after 'lang', followed immediately with a function. This is not valid json.

EDIT

It appears that the readme was incorrect. I had to to pass an array with the string 'twitter'.

var converter = new Showdown.converter({extensions: ['twitter']});
converter.makeHtml('whatever @meandave2020');
// output "
whatever @meandave2020
"

I submitted a pull request to update this.