Here's what this looks like:

I need to figure out the right way to handle licensing of bundled software like this - it's MIT licensed which is compatible with Datasette's Apache 2 license, but I feel like bundled licensed software (including codemirror) needs to be recognized in the README or docs somehow.

Let's only show the "Format SQL" button if the user has JavaScript enabled. We can do that in this code here:

https://github.com/bsmithgall/datasette/blob/4a7151a58d6ab7c8404a91beef7083e8a5807cf8/datasette/templates/_codemirror_foot.html#L14-L21

On the licensing front: it looks like the way Django handles this is to keep the licensing header in the files intact, e.g. https://github.com/django/django/blob/6deaddcca367d0143c815aaa42342021baa3b41e/django/contrib/admin/static/admin/js/vendor/jquery/jquery.js

So for this change, adding a comment at the top of sql-formatter.min.js which references the MIT license would do the trick.

I can work on that -- would you prefer to inline a display: hidden and then have the javascript flip the visibility or include it as css?

I'd prefer to have the JavaScript actually manipulate the DOM to add the button - something like this:

var button = document.createElement('button');
button.value = 'Format SQL';
button.addEventListener(
    'click', format, false
);
document.getElementById('run-sql').parentNode.appendChild(button);

I've implemented that approach in 86ac746. It does cause the button to pop in only after Codemirror is finished rendering which is a bit awkward.

Closing this because this feature was shipped in #592