I'm using this NPM package to get the CSV output of table from an access database.
I have my function structured as follows:
function createDB(mdbfile){
var rawDB = mdb(mdbfile);
var db = {}
rawDB.tables(function(err, table){
table.forEach(function(item){
var rawTable = null;
rawDB.toCSV(item, function(err, csv){
rawTable = csv; //Doesn't work
});
console.log(rawTable); //Always null :(
var newTable = Do stuff with CSV;
db.item = newTable;
});
});
return db
}I'm sure this is some scoping issue but I'm new to node and don't know how to search for this properly. From what I can tell the module is synchronous but the scope doesn't work.
Any help would be appreciated! Unfortunately a client I have MUST use access DB file and I'm just trying to make this work.
The scoping looks fine, but the toCsv function does not look synchronous. You can double check the source code: https://github.com/maxogden/node-mdb/blob/master/index.js. So, you would try to print out rawTable before the toCsv callback is called.
I would also add proper error handling within both callbacks to see whether you are getting any errors.
EDIT:
Since your createDB function makes asynchronous calls, it should take a callback. The code below is an example that could possibly work for your case.
// look into the async module, specifically forEach
const asyncForEach = require('async/forEach');
function createDB(mdbfile, next ){
var rawDB = mdb(mdbfile);
var db = {}
rawDB.tables(function(err, table){
if( err ) return next(err);
asyncForEach(
table,
function(item, cb){
rawDB.toCSV(item, ( err, csv )=>{
if( err ) return cb( err );
// this processing can be done here or in the callback to asynForEach
var newTable = Do stuff with CSV;
db.item = newTable;
cb(null, csv);
};
},
function(err, csvs){
// csvs can be processed and added to db here as well
if ( err ) return next( err );
return next( null, db );
} );
} );
}
You would then have to provide a callback to createDB when you call it:
createDB( mdbFile , ( err, db )=>{
if( err ) return err;
// use db e.g. res.send( db )
}
Or you could look into how to accomplish this with promises.