Copy operation doesn't deep clone, only references

[alshakero]

No description provided.

[felixfbecker]

Why is that a problem?

[tomalec]

It may be for someone expecting resulting object to be a JSON tree. You cannot use JSON syntax to create reference, you can only create two identical nodes.

let obj = {
  foo: {
    bar: 'baz'
  }
};
jsonpatch.applyOperation(obj, {op: 'copy', path: 'copied', from: 'foo'});

at this point your object looks like:

obj:
  foo: {
    bar: 'baz'
  },
  foo: {
    bar: 'baz'
  }
};

with current implementation

jsonpatch.applyOperation(obj, {op: 'replace', path: 'copied/bar', from: 'buz'});

changes also foo/bar. Which is pretty confusing as jsonpatch.applyOperation(JSON.parse(JSON.stringify(obj)), {op: 'replace', path: 'copied/bar', from: 'buz'}); will not.

I think that's a difference between "copy" and "attach"

https://tools.ietf.org/html/rfc6902#section-4.5:

This operation is functionally identical to an "add" operation at the
target location using the value specified in the "from" member.

"Value" not "reference".

[alshakero]

Closing as fixed in #134