这段查找两个对象数组之间差异的代码是如何工作的？

Question

我已经从 SO 的回答中测试了这段代码，它基本上 returns 只有数组 1 中存在而数组 2 中不存在的项目。但我不知道这是如何工作的，有人可以解释一下吗？

const arrayOne = [ 
  { value: "4a55eff3-1e0d-4a81-9105-3ddd7521d642", display: "Jamsheer" },
  { value: "644838b3-604d-4899-8b78-09e4799f586f", display: "Muhammed" },
  { value: "b6ee537a-375c-45bd-b9d4-4dd84a75041d", display: "Ravi" },
  { value: "e97339e1-939d-47ab-974c-1b68c9cfb536", display: "Ajmal" },
  { value: "a63a6f77-c637-454e-abf2-dfb9b543af6c", display: "Ryan" },
];

const arrayTwo = [
  { value: "4a55eff3-1e0d-4a81-9105-3ddd7521d642", display: "Jamsheer"},
  { value: "644838b3-604d-4899-8b78-09e4799f586f", display: "Muhammed"},
  { value: "b6ee537a-375c-45bd-b9d4-4dd84a75041d", display: "Ravi"},
  { value: "e97339e1-939d-47ab-974c-1b68c9cfb536", display: "Ajmal"},
];

const results = arrayOne.filter(({ value: id1 }) => !arrayTwo.some(({ value: id2 }) => id2 === id1));

console.log(results);

我觉得{ value: id1 }是解构赋值，不过好像调换了key和value？？？和id2 === id1有什么关系？

Answer 1

{ value: id1 } 将属性分配给另一个名称的变量。

例如：

({ a:id, b } = { a: 10, b: 20 });
console.log(id); // 10
console.log(a); // "Uncaught ReferenceError: a is not defined"

2. 将value分配给id1 & id2后，现在我们可以检查arrayOne中的id1和[=21=中的id2 ]

const arrayOne = [ 
  { value: "4a55eff3-1e0d-4a81-9105-3ddd7521d642", display: "Jamsheer" },
  { value: "644838b3-604d-4899-8b78-09e4799f586f", display: "Muhammed" },
  { value: "b6ee537a-375c-45bd-b9d4-4dd84a75041d", display: "Ravi" },
  { value: "e97339e1-939d-47ab-974c-1b68c9cfb536", display: "Ajmal" },
  { value: "a63a6f77-c637-454e-abf2-dfb9b543af6c", display: "Ryan" },
];

const arrayTwo = [
  { value: "4a55eff3-1e0d-4a81-9105-3ddd7521d642", display: "Jamsheer"},
  { value: "644838b3-604d-4899-8b78-09e4799f586f", display: "Muhammed"},
  { value: "b6ee537a-375c-45bd-b9d4-4dd84a75041d", display: "Ravi"},
  { value: "e97339e1-939d-47ab-974c-1b68c9cfb536", display: "Ajmal"},
];

const results = arrayOne.filter(
                        ({ value : id1  }) => !arrayTwo.some(
                                            ({ value: id2 }) => id2 === id1)
                );
console.log(results);

同解

const results = arrayOne.filter(
                        item1 => !arrayTwo.some( item2 => item1.value === item2.value)
                );
console.log(results);

const arrayOne = [ 
  { value: "4a55eff3-1e0d-4a81-9105-3ddd7521d642", display: "Jamsheer" },
  { value: "644838b3-604d-4899-8b78-09e4799f586f", display: "Muhammed" },
  { value: "b6ee537a-375c-45bd-b9d4-4dd84a75041d", display: "Ravi" },
  { value: "e97339e1-939d-47ab-974c-1b68c9cfb536", display: "Ajmal" },
  { value: "a63a6f77-c637-454e-abf2-dfb9b543af6c", display: "Ryan" },
];

const arrayTwo = [
  { value: "4a55eff3-1e0d-4a81-9105-3ddd7521d642", display: "Jamsheer"},
  { value: "644838b3-604d-4899-8b78-09e4799f586f", display: "Muhammed"},
  { value: "b6ee537a-375c-45bd-b9d4-4dd84a75041d", display: "Ravi"},
  { value: "e97339e1-939d-47ab-974c-1b68c9cfb536", display: "Ajmal"},
];

// The same solution
const results = arrayOne.filter(
                        item1 => !arrayTwo.some( item2 => item1.value === item2.value)
                );
console.log(results);

Answer 2

我想说理解它的最好方法是使用一些老式的 vanilla JS 进行重构：

const results = arrayOne.filter(objectOne => {
  return !arrayTwo.some(objectTwo => {
    return objectOne.value === objectTwo.value;
  })
});

这里我没有使用对象解构，也没有省略return关键字，这让事情更清楚了。

这段查找两个对象数组之间差异的代码是如何工作的？

How this code to find difference betwen two array of objects works?

javascript

ecma

node.js

ecmascript-6