Node + Sequelize: How to check if item exists before adding? (async confusion)
Author.count isn't really needed, unless you need the count. See findOrCreate().
With findOrCreate() you could have the following. (Edited trex005's snippet for this)
async.eachSeries(authors, function(item, callback) { Author.sync().then(function() { Author.findOrCreate({ where: { name: item.trim() }, defaults: { // set the default properties if it doesn't exist name: item.trim() } }).then(function(result) { var author = result[0], // the instance of the author created = result[1]; // boolean stating if it was created or not if (!created) { // false if author already exists and was not created. console.log('Author already exists'); } console.log('Created author...'); callback(); }); })})
Change your each to eachSeries and actually call the callback and you should be golden.
async.eachSeries(authors, function(item, callback){ Author.sync().then(function(){ Author.count({ where: {name: item.trim()} }).then(function(count){ if (count != 0) { console.log('Author already exists') callback(); //assuming you want it to keep looping, if not use callback(new Error("Author already exists")) } else { console.log('Creating author...') Author.create({ name: item.trim() }).then(function(author){ callback(); }) } }) }) })