Funny thing with json_decode...
$ php <?php echo var_export(json_decode("true ", true), true) ?> NULL
(Press ctrl-d after you write "?>".)
The same using node.js:
$ node > JSON.parse("true ") true > exit
Of course it could be argued that it's a good feature to not ignore leading white spaces. However most text editors are going to write at least one line break at the end of files -- and that kind of line break was the problem of my bug at the moment.