Object.assign strange behavior under jvm nashorn engine

[denghongcai]

reproduce step:
0. install jdk8

1. run jjs command, enter interactive shell
2. run load('./core.js'), browser version core-js bundle
3. run JSON.stringify(Object.assign({}, {1:2}, {x:1}))

output: {"x":1}

and if integer key is long enough, it works

[zloirock]

Seems the answer here:

[zloirock]

Fixed in v3 branch, thanks for the interesting issue -)