Meteor.methods() converts Float32Array to Object

Question

I'm working in Meteor.js with the recorderJs library, and trying to store stereo audio buffers to MongoDB.

On the client, console.log(buffers) gives an array of the form

[Float32Array, Float32Array]

But after passing it to Meteor.methods with Meteor.call('newSound', buffers) with the method

Meteor.methods({
    newSound: function(buffers) {
        console.log(buffers);
    }
}

I get an array like this:

[Object, Object]

Why is Meteor converting the arrays to objects? Upon retrieval, I need to work with the data as array buffers, and can re-convert them with

var buffers = new Array(
    _.toArray(buffers[0]),
    _.toArray(buffers[1])
);

but I'm concerned about performance. Should I be converting the buffers to blobs before storing them to the database, then reconverting when I retrieve them?

Answer 1

Only EJSON compatible types will be automatically converted from JSON objects to their actual JavaScript type. Read about EJSON here:

http://docs.meteor.com/#ejson

I don't believe Float32Array has been made EJSON compatible by the Meteor team. For more information on EJSON and how you can make a type compatible, watch these videos:

• What is EJSON?

• EJSON in Methods and Subscriptions

• Create a Custom EJSON Type

There is also EJSON.newBinary() which may be helpful for you.