function getPrevMap(from) {
        if (typeof options.map.prev === 'string') {
            var mapPath = options.map.prev + path.basename(from) + '.map';

            if (grunt.file.exists(mapPath)) {
                return grunt.file.read(mapPath);
            }
        }
    }
function getPrevMap(from) {
        if (typeof options.map.prev === 'string') {
            var mapPath = options.map.prev + path.basename(from) + '.map';

            if (grunt.file.exists(mapPath)) {
                return grunt.file.read(mapPath);
            }
        }
    }
function getPrevMap ( from ) { if ( typeof options . map . prev === 'string' ) { var mapPath = options . map . prev + path . basename ( from ) + '.map' ; if ( grunt . file . exists ( mapPath ) ) { return grunt . file . read ( mapPath ) ; } } }
Returns an input map contents if a custom map path was specified
@param {string} from Input CSS path
@returns {?string}
Returns an input map contents if a custom map path was specified