forEach using generators in Node.js

foreach, generator, koa, mongoose, node.js

Solution

Thanks guys, I've done this using the 'CO' module. Thanks.

var co = require('co');

items.forEach(co(function* (item) {
  var img = yield db.collection.findOne({id: item.id}).exec();
}));

EDIT: With the latest version of CO, you need co.wrap() for this to work.

Problem

I'm using Koa.js framework and Mongoose.js module. Normally to get a result from MongoDB I code like this: ``` var res = yield db.collection.findOne({id: 'my-id-here'}).exec(); ``` But I need to execute this line for every element of an array named 'items'. ``` items.forEach(function(item) { var res = yield db.collection.findOne({id: item.id}).exec(); console.log(res) // undefined }); ``` But this code doesn't run as yield is in the function. If I write this: ``` items.forEach(function *(item) { var res = yield db.collection.findOne({id: item.id}).exec(); console.log(res) // undefined }); ``` I'm not getting the result in res variable either. I tried to use 'generator-foreach' module but that didn't worked like this. I know that this is my lack of knowledge about the language literacy of Node.js. But can you guys help me finding a way how to do this?

Original source