仅当键匹配时合并2个对象数组

Question

我有2个对象数组，我想合并它们的属性，只有当user从两个数组匹配。

例子数组

arr1 = [{ bank: 1, user: 'fred', depositAmount: 100, withdrawalAmount: 0 }];
arr2 = [{ user: 'fred', gender: 'male', age: 27, state: "arizona" }, { user: 'john',gender: 'male', age: 28, state: "texas" }];

预期输出

arr1 = [{ bank: 1, user: 'fred', depositAmount: 100, withdrawalAmount: 0, gender: 'male', age: 27, state: "arizona" }];

这是我到目前为止尝试的，但它返回一个空数组

var result = [];
arr1.concat(arr2)
.forEach(item =>
result[item.user] =
Object.assign({}, result[item.user], item)
);
result = result.filter(r => r);
console.log(result)

Answer 1

您可以通过使用map,filter数组功能和spread operator(https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Spread_syntax):

)来实现。

const arr1 = [{ bank: 1, user: 'fred', depositAmount: 100, withdrawalAmount: 0 }, { user: 'john2',gender: 'male', age: 28, state: "texas" }];
const arr2 = [{ user: 'fred', gender: 'male', age: 27, state: "arizona" }, { user: 'john',gender: 'male', age: 28, state: "texas" }];
const newArray = arr1.map((obj) => {
const secondArrayObj = arr2.find((obj2) => obj2.user === obj.user);
if (secondArrayObj) {
return {...secondArrayObj, ...obj}
}
return null;
}).filter((obj) => obj != null);
console.log(newArray); 
//[{
//  "user": "fred",
//  "gender": "male",
//  "age": 27,
//  "state": "arizona",
//  "bank": 1,
//  "depositAmount": 100,
//  "withdrawalAmount": 0
//}] 

注意，如果两个对象中有相同的字段，arr2对象中的字段将被arr1对象中的字段覆盖