Instructor: Now, all the interesting is
allowJs.
With allowJs and by the way all the way we have
checkJs you can always include JavaScript
files in the compilation.
Now with allowJs a JavaScript file will be
compiled by type script so even if doesn't end
with .ts, type script will compile it
with checkJs it will not compile it but it
will still check the syntax in there and
report potentially errors.
This could be nice if you don't really wanna use
type script but you wanna take advantage
of some of its features and as far as
type script can help you with the any type only
which is effectively what you have in
JavaScript it will do so if you enable
these options.
Now we don't need it for this project
and for this project we would want to
make sure we don't double compile these
JavaScript files which do stem from
type script files so we would have to tweak
the include and exclude settings a bit
but you could use that in projects where you don't
wanna use type script at all or where for whatever
reason you have some vanilla JavaScript files
next to your type script files and you wanna
check the vanilla JavaScript files as well.
Now let's fast forward a bit, jsx is an option
that can help you with react js which does not really
matter for us here, declaration and declarationMap
is also not important here.
Dts files are an advanced concept which matter
to you if you're shipping your project as a
library to other people and you need basically
a manifest file which describes all the
types you have in your project, that's such
a .d.ts file.
Source map is an interesting one though.