Unable to serialize Javascript object with JSON.stringify()

I have an object that looks like this when I do console.log()

0:
faceLandarks: [{...},...]
image: canvas
leftHandLandmarks: [{...},...]

There’s more, but you get the idea.
When I try to serialize the object with JSON.stringify() the image type (canvas) is lost. I need a way to keep all the data in the object when I serialize it without having to import a library through npm or similar.

I can add more Javascript files, but cannot use npm.