How does mongodb handle HTML5/Javascript typed arrays?

Question

I am interacting with a mongodb through Javascript.

Is there any difference between the following two statements?

myCollection.insert({tiles: new Int32Array(256)});
myCollection.insert({tiles: new Array(256)});

Answer 1

Yes, it's very different.

The first using Int32Array , which isn't a JavaScript type that the current driver uses/understands, instead becomes projected into an object with properties following the indices of the array:

"tiles" : { "0" : 0, "1" : 0, "2" : 0.... }

The second translates to an Array in MongoDB, of type Null .

"tiles": [ null, null, null .... ]

So, the first does not remain as an array, while the second one does.