使用with key及其后缀从对象创建数组

Question

在寻找使用键将对象转换/分组为数组的帮助时，键与其后缀(-)有所不同。

const obj = {
    "name-1":"a", 
    "age-1":"20", 
    "email-1":"a@email.com", 
    "name-2":"b", 
    "age-2":"24", 
    "email-2":"b@email.com", 
    "name-3":"c", 
    "age-3":"22", 
    "email-3":"c@email1.com"
};

预期结果

[
    {
        "name":"a", 
        "age":"20", 
        "email":"a@email.com"
    },
    {
        "name":"b", 
        "age":"24", 
        "email":"b@email.com"
    },
    {
        "name":"c", 
        "age":"22", 
        "email":"c@email.com"
    }
]

可能由于错误的搜索关键字无法找到重复的问题。

Answer 1

您可以在Object.entries上运行一个reduce，并通过'-'拆分键，比如name-1, age-2等，然后返回一个对象数组。

​

const obj = {
    "name-1":"a", 
    "age-1":"20", 
    "email-1":"a@email.com", 
    "name-2":"b", 
    "age-2":"24", 
    "email-2":"b@email.com", 
    "name-3":"c", 
    "age-3":"22", 
    "email-3":"c@email1.com"
};

const res = Object.entries(obj).reduce((acc, [key, value]) => {
  const [ k, i ] = key.split('-');
  acc[i - 1] = acc[i - 1] || {};
  acc[i-1][k] = value;
  return acc;
}, [])

console.log(res);

​

在上面的reduce代码中，我将key拆分为'-'，它给出了一个对象的键和最后一个数组的索引。

然后检查数组中是否存在索引i - 1。如果不是，则由一个空对象初始化它。这里我使用i - 1，因为给定的对象键从1开始，而数组从0开始。

最后，我将对象值放入新创建的对象中。

Answer 2

这是一个很好的算法问题，我将用ES6语法来解决它。

多亏了一些函数，比如Object.entries和reduce，你就可以做到这一点

示例：

​

const obj = {
    "name-1":"a", 
    "age-1":"20", 
    "email-1":"a@email.com", 
    "name-2":"b", 
    "age-2":"24", 
    "email-2":"b@email.com", 
    "name-3":"c", 
    "age-3":"22", 
    "email-3":"c@email1.com"
};

const result = Object.entries(obj)
  // Here we destructure the entry with on the left the key, and value on the right
  .reduce((accumulator, [key, value]) => {
    const [property, index] = key.split('-');
    
    // Get the value currently being filled, or an empty object if it doesn't
    // exist yet.
    const entry = accumulator[index] || {};

    accumulator[index] = {
      // Spread the current entry to which we are adding
      // the property to the object being filled
      ...entry,
      // Dynamic key syntax
      [property]: value,
    };

    return accumulator;
  }, [])
  // Remove "holes" from the array since it's indexed with given keys
  .filter(value => value !== undefined);

console.log(result);

​