Confusing re-assignment about didact

[al3ksandrsafonov]

It's not a variable, so we don't overwrite nothing! It is an object, so we just change a link on it.
When index = 0 we have in memory the object newFiber_0 and 3 links on it:
newFiber => newFiber_0
wipFiber.child => newFiber_0 after operation wipFiber.child = newFiber
prevSibling => newFiber_0 after prevSibling = newFiber
Then index = 1 and we have in memory 2 objects(newFiber_0 and newFiber_1) and 3 links:
newFiber => newFiber_1
wipFiber.child => newFiber_0
prevSibling => newFiber_0
The operation prevSibling.sibling = newFiber adds the link on the object newFiber_1 to the object newFiber_0, so we have:
newFiber => newFiber_1
wipFiber.child => newFiber_0
wipFiber.child.sibling => newFiber_1
prevSibling => newFiber_0
After operation prevSibling = newFiber:
newFiber => newFiber_1
wipFiber.child => newFiber_0
wipFiber.child.sibling => newFiber_1
prevSibling => newFiber_1
Then index = 2 and we have in memory 3 objects(newFiber_0, newFiber_1, newFiber_2) and links:
newFiber => newFiber_2
wipFiber.child => newFiber_0
wipFiber.child.sibling => newFiber_1
wipFiber.child.sibling.sibling => newFiber_2
prevSibling => newFiber_2
And so on...

[joshuaalpuerto]

Wow @al3ksandrsafonov Thank you for you explanation I get it now. Basically it mutates the wipFiber.child since prevSibling has link to the newFiber object.

[dbwcooper]

@joshuaalpuerto @al3ksandrsafonov , thanks for you explanation, the key point is object is reference type.