Method visitPropertiesOrArrayEntries is doing unnecessary iterations on updateViewModel because the wrong variable is being used to check against ignored properties.

[gracezlive]

In a data model that contains many nested collections, it's essential to avoid unnecessary recursions. We have been using "ignore" to prune any deep branches in our data model that could cause stack overflow during mapping. However the method visitPropertiesOrArrayEntries is incorrectly checking a property name against the ignore option, at a sub-collection level, so all our ignored properties are being visited by updateViewModel anyway.

Current line 443: if (ko.utils.arrayIndexOf(options.ignore, fullPropertyName) != -1) {

It should be: if (ko.utils.arrayIndexOf(options.ignore, indexer) != -1) {

And the same issue is with copy and observe.