[recovery] Unclosed contexts are ignored

[ljharb]

https://web.archive.org/web/20201110211135/https://github.com/substack/subarg/issues/7

filed by @fiberthrone

I've realized that in cases like the one below unclosed contexts are just ignored by subarg without any error:

subarg(['abc', '[', 'cde']) // returns { _: [ 'abc' ] }

This may cause unexpected behavior.
For example, this is a usual browserify (which uses subarg) run:

browserify app.jsx -t [ babelify --presets [ react es2015 ] ]

However, the command below will just ignore everything after the -t arg, because double brackets close a context only once.

browserify app.jsx -t [ babelify --presets [ react es2015 ]]

Should subarg inform of an error in some way in such cases?