Question

我正在尝试创建一个对象，如果需要，该对象在创建时的键被创建为OrderedMaps。

即

OrderedMap().setIn(['users','subusers'], OrderedMap())

我想要什么

OrderedMap->users->OrderedMap()->subusers->OrderedMap()

我真正得到的是什么

OrderedMap->users->Map()->subusers->OrderedMap()

是否有任何简单的方法可以获得仅包含OrderedMaps的OrderedMap？

Answer 1

不幸的是，所有whateverIn函数都以updateIn结尾，该函数使用emptyMap()作为其notSetValue。我猜想添加一个类似于Immutable的fromJS的reviver函数将是一个好主意，并且可能被接受为Issue / Pull Request。

请注意，当您从头开始构建完整的树时，您可能只想将fromJS与自定义齐磊器一起使用。这是ImmutableJS文档中示例的副本：

const { fromJS, isKeyed } = require('immutable@4.0.0-rc.9')
fromJS({ a: {b: [10, 20, 30]}, c: 40}, function (key, value, path) {
  console.log(key, value, path)
  return isKeyed(value) ? value.toOrderedMap() : value.toList()
})

下面是一个更新程序函数，它改用OrderedMap。

let map = Immutable.OrderedMap({key0:Immutable.OrderedMap()}).setIn(['key0','key1', 'key2', 'key3'], 'banana');

function check(what, name) {
  console.log('verify map using', name);
  let entry = what.entrySeq().first();

  while(entry) {
    if (Immutable.isImmutable(entry[1])) {
      console.log(`${entry[0]} is ${Immutable.isOrdered(entry[1]) ? '' : 'un'}ordered`);
      entry = entry[1].entrySeq().first();
    } else {
      console.log(`${entry[0]} = ${entry[1]}` );
      entry = null;
    }
  }
}

check(map, 'setIn');


function orderedUpdateIn(what, path, value) {
  if (what.has(path)) {
    return what.setIn(path, value);
  }
  
  let missingPath = [], existingPath = [];
  let pathMap = what;
  
  // figure out what part is missing
  for (let i = 0;i < path.length; i++) {
    pathMap = pathMap.get(path[i]);
    if (!pathMap) {
      missingPath = path.slice(i);
      existingPath = path.slice(0,i);
      break;
    }
  }
  
  // build missing part
  let valueToSet = Immutable.OrderedMap({ 
    [missingPath[missingPath.length - 1]]: value
  });
  
  for (let i = missingPath.length - 1;i >= 0; i--) {
    valueToSet = Immutable.OrderedMap({
      [missingPath[i]]: valueToSet
    });
  }

  return map.setIn(existingPath, valueToSet);
}

map = orderedUpdateIn(Immutable.OrderedMap({key0:Immutable.OrderedMap()}), ['key0','key1', 'key2', 'key3'], 'banana');
check(map, 'updateIn');

<script src="https://cdnjs.cloudflare.com/ajax/libs/immutable/4.0.0-rc.12/immutable.js"></script>

immutablejs mergeIn如果没有密钥，则OrderedMap返回Map

1 个答案: