merging objects delete initial keys-CodePudding

I have two objects obj1 & obj2.

when I merge with:

const obj1 = {
  error_to_retrieve: "teste",
  error_to_search_customer: "",
  error_to_sync_timezone: "",
  error_to_update_avatar: "",
  error_to_update_profile: "",
  error_to_validate_customer_token: "",
  expired_session: "",
  invalid_token: "",
  invalid_token_text: ""
}

const obj2 = {
  error_to_retrieve: "test",
  error_to_search_customer: "test",
  error_to_sync_timezone: "test",
  error_to_update_avatar: "test",
  error_to_validate_customer_token: "test",
  expired_session: "test",
  invalid_token: "test",
  invalid_token_text: "test"
}


const obj3 = {...obj1, ...obj2};

console.log(obj3);

I get the full obj2, and it dont have the key error_to_update_profile.

How I maintain the key of the first object that my second dont have?

CodePudding user response：

Use Object.prototype.hasOwnProperty() to check whether your final objects has the property key error_to_update_profile. The funtion returns true which is prove that the merge worked perfectly fine as intended.

const obj1 = {
  error_to_retrieve: "teste",
  error_to_search_customer: "",
  error_to_sync_timezone: "",
  error_to_update_avatar: "",
  error_to_update_profile: "",
  error_to_validate_customer_token: "",
  expired_session: "",
  invalid_token: "",
  invalid_token_text: ""
};

const obj2 = {
  error_to_retrieve: "test",
  error_to_search_customer: "test",
  error_to_sync_timezone: "test",
  error_to_update_avatar: "test",
  error_to_validate_customer_token: "test",
  expired_session: "test",
  invalid_token: "test",
  invalid_token_text: "test"
};

const obj3 = { ...obj1, ...obj2 };

console.log(obj3.hasOwnProperty("error_to_update_profile"));

CodePudding user response：

You can change the order of what to write, i.e. whatever you put last will overwrite all previous entries { ...obj2, ...obj1 } → obj1 will overwrite obj2 if there are duplicate keys