这是一个递归的ES6实现，它也可以清理属性的属性。它是一个副作用自由函数，意味着它不修改对象，因此必须使用返回对象。

function removeUndefinedProperties(obj) {
  return Object.keys(obj || {})
    .reduce((acc, key) => {
      const value = obj[key];
      switch (typeof value) {
        case 'object': {
          const cleanValue = removeUndefinedProperties(value); // recurse
          if (!Object.keys(cleanValue).length) {
            return { ...acc };
          }
          return { ...acc, [key]: cleanValue };
        }
        case 'undefined':
          return { ...acc };
        default:
          return { ...acc, [key]: value };
      }
    }, {});
}

在TypeScript中，使用unknown输入它，例如:

function removeUndefinedProperties(obj: unknown): unknown {
  return Object.keys(obj ?? {})
    .reduce((acc, key) => {
      const value = obj[key];
      switch (typeof value) {
        case 'object': {
          const cleanValue = removeUndefinedProperties(value); // recurse
          if (!Object.keys(cleanValue).length) {
            return { ...acc };
          }
          return { ...acc, [key]: cleanValue };
        }
        case 'undefined':
          return { ...acc };
        default:
          return { ...acc, [key]: value };
      }
    }, {});
}

ES6 arrow function and ternary operator:
Object.entries(obj).reduce((acc, entry) => {
   const [key, value] = entry
  if (value !== undefined) acc[key] = value;
  return acc;
}, {})


    const obj = {test:undefined, test1:1 ,test12:0, test123:false};
    const newObj = Object.entries(obj).reduce((acc, entry) => {
       const [key, value] = entry
      if (value !== undefined) acc[key] = value;
      return acc;
    }, {})
    console.log(newObj)

如果有人需要欧文(和埃里克)答案的递归版本，这里是:

/**
 * Delete all null (or undefined) properties from an object.
 * Set 'recurse' to true if you also want to delete properties in nested objects.
 */
function delete_null_properties(test, recurse) {
    for (var i in test) {
        if (test[i] === null) {
            delete test[i];
        } else if (recurse && typeof test[i] === 'object') {
            delete_null_properties(test[i], recurse);
        }
    }
}

这是另一种选择

打字稿:

function objectDefined <T>(obj: T): T {
  const acc: Partial<T> = {};
  for (const key in obj) {
    if (obj[key] !== undefined) acc[key] = obj[key];
  }
  return acc as T;
}

Javascript:

function objectDefined(obj) {
  const acc = {};
  for (const key in obj) {
    if (obj[key] !== undefined) acc[key] = obj[key];
  }
  return acc;
}

30多个答案，但我没有看到这个简短的ES6一行程序，由于Object.assign()是一个无声地忽略任何非对象(如false)的变参数函数，因此利用了扩散操作符。

Object.assign({}, ...Object.entries(obj).map(([k,v]) => v != null && {[k]: v]))

JSON。Stringify删除未定义的键。

removeUndefined = function(json){
  return JSON.parse(JSON.stringify(json))
}