如何在 ImmutableJS 中更新列表中的列表？

Question

我在更新 ImmutableJS 列表中的列表时遇到问题。谁能告诉我我做错了什么？

var rows = Immutable.List();
for (var i = 0; i < 12; i++) {
  rows = rows.push({type:"floor"});
}

var cols = Immutable.List();
for (var j = 0; j < 12; j++) {
  cols = cols.push(rows);
}

var wall = {type:"wall"};

cols = cols.update(cols.get(3).get(4), function(wall) { return wall});

// I expect to get 'wall' written in the console, but the output is 'floor'.
console.log(cols.get(3).get(4).type);

<script src="https://cdnjs.cloudflare.com/ajax/libs/immutable/3.7.6/immutable.js"></script>

Answer 1

您可以将更新分为两个步骤（参见 jsfiddle 上的示例）：

var rows = Immutable.List();
for (var i = 0; i < 12; i++) {
  rows = rows.push({type:"floor"});
}

var cols = Immutable.List();
for (var j = 0; j < 12; j++) {
  cols = cols.push(rows);
}

var wall = {type:"wall"};
var nestedList = cols.get(3);
var newNestedList;
var newCols;
newNestedList = nestedList.update(4, function(item) {return wall});
newCols = cols.update(3, function(list) { return newNestedList});
console.log(newCols.get(3).get(4).type);

如何在 ImmutableJS 中更新列表中的列表？

How to update list in list in ImmutableJS?

immutable.js