gulp-changed doesn't work with a function inside of changed()

Question

I installed gulp-changed on my scripts task and it works fine if I pass a string into it (ex: 'output/'). But on my project I'm using a function that returns the dest to be the same as the source:

gulp.task('scripts', function(){
    gulp.src([
            'assets/scripts/**/*.js',
            '!assets/scripts/**/_*.js',
            '!assets/scripts/**/*.min.js'
        ])

        // 1* it works fine with a string
        //.pipe(gulpif(global.isWatching, changed( 'output/' ) ))

        // 2* it doesn't work with the function
        .pipe(gulpif(global.isWatching, changed( function(file) { return file.base; } ) ))

        .pipe(include())
            .on('error', console.log)
        .pipe(babel({
            presets: ['es2015'],
            compact: true
        }))
        .pipe(gulpif(env === "production", uglify().on('error', gutil.log)))
        .pipe(rename({ suffix: '.min' }))

        //.pipe(gulp.dest( 'output/' ));

        //it works if i don't apply changed with a function
        .pipe(gulp.dest( function(file) { return file.base; } ));

});

What am i doing wrong? Maybe I need to change the function. I still want to have the dest the same as the src.

Thanks