lib/main.js
function(chapterSlug, chunkSlug) {
            let file = path.join(container_directory, content_dir, chapterSlug, chunkSlug + '.' + this.chunkExt);
            return fs.readFileSync(file, {encoding: 'utf8'});
        }
function(chapterSlug, chunkSlug) {
            let file = path.join(container_directory, content_dir, chapterSlug, chunkSlug + '.' + this.chunkExt);
            return fs.readFileSync(file, {encoding: 'utf8'});
        }
Returns the contents of a chunk.
If the chunk does not exist or there is an exception an empty string will be returned.
@param chapterSlug
@param chunkSlug
@returns string the contents of the chunk