Gulp - uglify() with wildcard in source throws error

Question

When running the final build step in GULP, I am trying to use uglify with a wildcard in the gulp.src, but seeing an error.

This works:

gulp.task('build', ['lint','karma','clean'], function () {
return gulp.src('./src/js/file.js')
    .pipe(gulp.dest('./dist'))
    .pipe(uglify())
    .pipe(size())
    .pipe(gulp.dest('./dist'));
});

But this doesn't:

gulp.task('build', ['lint','karma','clean'], function () {
return gulp.src('./src/js/*.js')
    .pipe(gulp.dest('./dist'))
    .pipe(uglify())
    .pipe(size())
    .pipe(gulp.dest('./dist'));
});

The only difference being that I select a specific file in the working gulp.src, but use a wildcard in the non-working version. I have narrowed this down to uglify() because if I comment it out, I don't get the error, and everything completes without issue.

Any help would be greatly appreciated