index.js
function _getSHA(id, callback) {
        repo.contents("").fetch({
            ref: options.branch
        }, function(err, res) {
            if (err) return callback(err);
            var sha = res.reduce(function(previousValue, item) {
                return item.name === id ? item.sha : previousValue;
            }, "");
            callback(err, sha);
        });
    }
function _getSHA(id, callback) {
        repo.contents("").fetch({
            ref: options.branch
        }, function(err, res) {
            if (err) return callback(err);
            var sha = res.reduce(function(previousValue, item) {
                return item.name === id ? item.sha : previousValue;
            }, "");
            callback(err, sha);
        });
    }
function _getSHA ( id , callback ) { repo . contents ( "" ) . fetch ( { ref : options . branch } , function ( err , res ) { if ( err ) return callback ( err ) ; var sha = res . reduce ( function ( previousValue , item ) { return item . name === id ? item . sha : previousValue ; } , "" ) ; callback ( err , sha ) ; } ) ; }
get the SHA corresponding to id at the HEAD of options.branch

@access private
@param {String} id
@param {Function} callback called with (err, result)
get the SHA corresponding to id at the HEAD of options . branch