function onJSON( error, pkg ) {
		var j = i + 1;
		if ( error ) {
			debug( 'Encountered an error when searching for an `include` directory: %s (%d of %d). Error: %s', files[ i ], j, total, error.message );
		} else if ( pkg.directories && pkg.directories.include ) {
			debug( 'Detected an `include` directory.' );
			out.push( resolve( dirname( files[ i ] ), pkg.directories.include ) ); // eslint-disable-line max-len
		} else {
			debug( 'Unable to detect an `include` directory.' );
		}
		return done();
	}
Callback invoked after reading a package's `package.json` file.

@private
@param {(Error|null)} error - error object
@param {JSON} pkg - package meta data
@returns {void}