IE10+, Firefox: "Invalid calling object" on properties after angular.copy of a File object

[nlwillia]

Given a file object, calling angular.copy and trying to access properties like "name" and "size" on the copy will result in a "Invalid calling object" error being thrown in IE 10+. In Firefox, the error is "Illegal operation on WrappedNative prototype object". Tested in angular 1.3 beta 15. (Demo) The problem does not occur in angular 1.1.5 or in Chrome.

[btford]

My recommendation would be to write your own util for copying specific options.

angular.copy's implementation is tailored to Angular's internal needs and implemented with certain performance characteristics in mind. For many cases, this utility works well in application logic, but when you need to retain certain special object characteristics (like some proto chain or non-enumerable property), you should write or use another utility.

[nlwillia]

Sure. It might be worth giving a nod to this in the docs.

[btford]

Agreed. We get many issues regarding this. /cc @IgorMinar

[gkalpak]

Let's track the issue in #14352.