.jshintrc

changelog: make copies related function return None or a valid value

With the previous code, existing but empty value were not "decoded", leading to
the method returning one of `None`, some valid value (`list` or `dict`) or
`b''`.

On a general basis, not explicitly checking for None is a source of bugs.
Having a clean return types will help the side-data copies code in future
changesets.

Differential Revision: https://phab.mercurial-scm.org/D7037

{
    // Enforcing
    "eqeqeq"        : true,     // true: Require triple equals (===) for comparison
    "forin"         : true,     // true: Require filtering for..in loops with obj.hasOwnProperty()
    "freeze"        : true,     // true: prohibits overwriting prototypes of native objects such as Array, Date etc.
    "nonbsp"        : true,     // true: Prohibit "non-breaking whitespace" characters.
    "undef"         : true,     // true: Require all non-global variables to be declared (prevents global leaks)

    // Environments
    "browser"       : true      // Web Browser (window, document, etc)
}