tags = object.tags -> Pass by reference?

[bjohas]

We've got a script here:
https://github.com/OSM-Utilities/JOSM-Scripts-HOT/blob/master/examples/nodeBuilding2Way.js

If you search for "pass-by-ref?", you'll see this comment:
// Does not work: If nodes[j].tags is set to null, tags also becomes null. pass-by-ref?

It appears that in "var tags = nodeBuilding[i].tags;", the element is passed by reference. If tags=null, then nodeBuilding[i].tags also becomes null.

Possibly related example here:
https://github.com/OSM-Utilities/JOSM-Scripts-HOT/blob/master/addOLC.js
(search for "pass-by-ref?").

Setting "var tags = object.tags" and later on object.tags=tags doesn't work.

Any thoughts on this?

[bjohas]

I received your response by email, but it doesn't show here. It makes sense to me that nodeBuilding[i] remains linked to the object.

However, why does tags in var tags = nodeBuilding[i].tags remain linked to the object?

I saw some stage things where operating on node.lon = function ( node.lat ) ended up overwriting node.lat (see geoutils.js in our repo). Couldn't really make sense of that :(
(c.f. exports.flatten = function(dataset)... else if (latlon.lat)... in https://github.com/OSM-Utilities/JOSM-Scripts-HOT/blob/master/lib/geoutils.js)

However, why does tags in var tags = nodeBuilding[i].tags remain linked to the object?

I deleted my previous responsive because I realized it was useless, since you were talking about the link quoted above and not about p.tags[something];