Meteor.bindEnvironment with node stream function loses context

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1

On calling a Meteor method with Meteor.bindEnvironment to create a new Fiber, the data context is no longer available. The insert ID returns undefined.

Meteor.call('saveData', data, function(error, result){
    let returnValue = Collection.findOne({'data': result }).buffer;
  }
});

Meteor.methods({
  'saveData': function(data) {
    let doc = new PDFDocument();
    doc.image(data, 0, 0);
    doc.pipe(concat(Meteor.bindEnvironment(
      function(buffer) {
        let newID = Collection.insert({
          'data': buffer,
        });
      }
    )));
  }
  doc.end();
  return newID;
});

I have attempted using Meteor.bindAsync because I thought I would have a new Fiber and the original data context, but I still get the error that Meteor must run within a Fiber. How can I bind newID to the original data context to pass it back once the insert has finished?

2

There’s a few things wrong with that method.

  1. let is block scoped: defining newID in your function{buffer) means it’s undefined outside of that function.
  2. You are declaring doc.end(); and return newID; entirely outside of the method.
  3. You will, I think, need to explicitly use Fibers/Futures to cope with that flow. Alternatively, consider using Promises and async/await and declare your method as async saveData(data) {.... Check out this article for more information on this approach.
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