package-lock.json has been generated with version 6.6 of npm (or
higher). In this version, npm updated the format, so to avoid
changes being done and undone to package-lock.json, we now tell
tools like Node version manager that we'd prefer a recent version
of Node.

See
https://stackoverflow.com/questions/54411377/package-lock-json-file-package-with-optional-true

Although package.json referenced Webpack, there was not actually a
configuration file for Webpack, and it could not be run
successfully. It appears that the code was published as-is.

I've now added a configuration file to pass the code through Babel,
using the current version of Babel. The module is still exported as
a default CommonJS module, but is now located in dist/main.js
instead of index.js.

This allows files to be written with a `.ts` extension, and for
actual TypeScript syntax to be used inside those files.

Note, though, that at this point the types are not actually
actively checked (unless by your editor). All this does is
stripping the type definitions and parsing the .ts files as
Javascript.

This activates type checking, failing the build if a .ts file does
not pass type checking. Strict mode is currently set to true,
which appears to be workable somewhat by only converting single
files to .ts, and then e.g. adding explicit `any` annotations in
places where it's currently too much work to add explicit types.

This allows files to be written with a `.ts` extension, and for
actual TypeScript syntax to be used inside those files.

Note, though, that at this point the types are not actually
actively checked (unless by your editor). All this does is
stripping the type definitions and parsing the .ts files as
Javascript.

This activates type checking, failing the build if a .ts file does
not pass type checking. Strict mode is currently set to true,
which appears to be workable somewhat by only converting single
files to .ts, and then e.g. adding explicit `any` annotations in
places where it's currently too much work to add explicit types.

…escript