Problem when trying to reassign an object altered with the LS delete operator with the latter's return value #273
Description
The title was hard to find for me, to make it clear and concise, but actually the problem is simple.
Whether this is a good practice or not, here is what I've done:
During one of my developments, I tried to do something I often do which is recursively traversing a tree from the root to the leaves, removing some properties on each node.
Here the tree had a simple from:
- the root
- each node has only ONE child node, except the leaf of course
Simple right?
Now the problem comes from the fact that the property I wanted to remove on each node during the operation was the child node itself.
So here was my first implementation:
let node = root
while node.child?
node = delete node.childConsidering the documentation, I would expect it to work.
However, looking at the compiled JavaScript:
(function(node){
while (node.child != null) {
node = node.child, delete node.child;
}
}.call(this, root));we see that the problem comes from the order of the operations: the node variable is assigned before the property is deleted, but here we wanted to delete a property of node.
This has been done this way to avoid a temporary variable I guess.
In the case I shew, there is a simple workaround, using an implicit variable acting as the missing temporary variable: the that reference coming from the test.
let node = root
while node.child?
delete node.child
node = thatHowever I think this is an issue, or otherwise change the documentation to be clear on this fact.