如何将两个对象合并到另一个对象中

Question

我有第一个对象

obj1 = {lastName: "", address1: "Some address"}

第二个对象：

obj2 = {lastName: "Salivan", address1: "1200 Getty Center Dr"}

在结果对象中：

obj3 = {lastName: "Salivan", address1: "Some address"}

Answer 1

对我来说最简单的方法是执行以下操作：

const newObject = {
    ...obj1,
    ...obj2,
}

问题是，它会凌驾于你的价值观之上！所以最好不要将两个相似的对象合并为一个，通常用于更新一个对象的值或将不同的对象合并为一个。

按照

@AlexSp3

的建议，您还可以：

obj3 = Object.assign(obj1, obj2)

对于您的具体情况：

const obj3 = {
   key1: '',
   key2: '',
}
if (!obj1.key1) {
   obj3.key1 = obj2.key1;
} else {
   obj3.key1 = obj1.key1;
}

// ... repeat with key2

Answer 2

如果目标是选择非错误值...

let obj1 = {
  lastName: "",
  address1: "Some address"
}
let obj2 = {
  lastName: "Salivan",
  address1: "1200 Getty Center Dr"
}

let result = Object.fromEntries(
  Object.entries(obj1).map(([key, value]) => {
    return [key, value || obj2[key]]
  })
);


console.log(result)

Answer 3

不覆盖值：

const obj1 = {
  key1: 1,
  key2: 2
}

const obj2 = {
  key2: 3,
  key3: 4
}

function mergeObjects(obj0, obj1) {
  // merge object keys into array
  const joined = [...Object.keys(obj0), ...Object.keys(obj1)]

  // remove duplicates
  const uniqueKeys = [...new Set(joined)]

  // merge obj0 and obj1 into new Object
  // obj1 overrides obj0
  const newObject = {}
  uniqueKeys.forEach(key => {
      if (obj0[key] !== undefined && obj1[key] !== undefined) {
          newObject[key] = [obj0[key], obj1[key]]
      } else if (obj0[key] === undefined && obj1[key] !== undefined) {
          newObject[key] = obj1[key]
      } else if (obj0[key] !== undefined && obj1[key] === undefined) {
          newObject[key] = obj0[key]
      } else {
          console.log('OBJECT MERGING ERROR')
      }
  })
  return newObject
}

console.log(mergeObjects(obj1, obj2))