The following bit of code will work fine as is when the list is unsorted. You
can add and remove persons as expected.
The problem crops up when we want the list to be sorted. Just adding in sorting
commands seems to change something that causes the wrong name to be associated
with the remove action. Any ideas how to fix this problem?
To see the bug, do the following:
1. Uncomment the call to `sorted` in line **A**
2. Uncomment the `sort` calls in lines **B** and **C**
3. Run the app
4. Add a person named otto
5. Click the `(x)` next to otto to delete him
Expected:
* otto is deleted and the list renders the other names in order
Actual:
* otto is not deleted
* The person alphabetically after otto is deleted
* This process is repeated each time you try to delete otto
include karax/prelude
import algorithm, sequtils
var
people: seq[string] = @["wendy", "sam", "nancy"] #.sorted # line A
newPersonName = ""
proc mkRemoveAction(person: string): proc() =
result = proc() =
echo "trying to remove " & person
people = filter(people,
proc(pA: string): bool =
pA != person)
# sort(people) # line B
echo "people = " & $people
proc createDom(): VNode =
result = buildHtml(tdiv):
h1: text "Example Bug"
tdiv:
input(`type` = "input"):
proc onchange(ev: Event, n: VNode) =
echo "value = " & n.value
newPersonName = $n.value
button(`type` = "button"):
text "Add Person"
proc onclick(ev: Event, n: VNode) =
echo "trying to add person: " & newPersonName
people.add(newPersonName)
# sort(people) # line C
echo "People = " & $people
ul:
for x in people:
li:
text x
span:
button(`type` = "button", onclick = mkRemoveAction(x)):
text "(X)"
setRenderer createDom
Run
