Ask HN: What's the Running Time of Node's Array.push and Array.unshift?

I don't know C/C++ very well, but I'm trying to figure out where `Array.push` is implemented on the Node source code. Is this one https://github.com/v8/v8/blob/master/src/builtins/builtins-array.cc#L145? Ultimately, what I want to know if the runtime of the Array.push and Array.unshift implementation. Based on the ECMA2019, It seems like push is O(1) https://tc39.github.io/ecma262/#sec-array.prototype.push and unshift is O(n)? https://tc39.github.io/ecma262/#sec-array.prototype.unshift