govuk-frontend-svelte

Playground for what could become a nunjucks -> svelte converter.

General idea:
* parse nunjucks template to AST
* transform nunjucks AST to svelte AST
* write (format) svelte template

Ideally we could contribute the tranformer and formatter back to meta-template
although that project has no concept of transformation currently.

For ideas we should look at babel etc.. These transpilers work the same way
as we're targeting - e.g. take typescript, build AST, transform AST, write
javascript.

translate.js is the entry point for this playground. Run it and it will
convert all macro.njk files in the govuk-frontend dependency into svelte
templates in build. The svelte template is called the macro name.

format.js is used to write out the AST in the svelte format. This
contains a number of Noop functions that need to be implemented for us to
get full support for the govuk nunjucks templates.

check.js iterates over all converted templates, renders them and compares
them. This isn't fully implemented as svelte doens't seem to have a renderer
or it renders as a component that will render itself when loaded in the
browser / called on the server - need to sort out.

Note though in check.js the svelte compile function returns an AST. This
be very useful to us as the result of the transformation on the nunjucks AST
should look like the svelte AST. It is probably worth hand coding some
svelte templates just to get a look at the AST, for example straight away
you can see it has html, css and script Fragment nodes un der the
root node.