在TypeScript中使用解构/扩展来复制具有重命名属性的对象

Question

I need a function that maps object from one type to another:

I have an object like this:

interface IEntityPerson {
  person_id: number
  name: string
  age: number
  address: IAddress
}

const orig: IEntityPerson = {
  person_id: 1,
  name: 'Ole',
  age: 40,
  address: myAddress
}

I want to use destructuring to map to another type where person_id is renamed to personId:

interface IRenamed {
  personId: number
  name: string
  age: number
  address: IAddress
}

const newObj: IRenamed = {
  personId: 1,
  name: 'Ole',
  age: 40,
  address: myAddress
}

I tried this but doesn't work:

export function mapContractTemplate(p: IEntityPerson): IRenamed {
  const renamed = {
    person_id: personId,
    ...rest
  } = p
  return renamed
}

How can I do this?

Also, notice that the 'address' property is a nested object. Is there a smart way to do this with destructuring and/or spreading?

Answer 1

Destructuring an object already defines the destructured properties as fields scoped to that block, they can't be assigned as a group to another field.

You can do it like this:

export function mapContractTemplate(p: IEntityPerson): IRenamed {
    const { person_id, address, ...rest } = p;
    return {
        personId: person_id,
        address: { ...address },
        ...rest
    }
}

This wil also create a copy of the address field, but it won't create a deep copy of it. So, in case address contains more nested objects or arrays you would have to do the nested destructuring manually.

Answer 2

Maybe you can simple copy all properties to the a new object and apply the specific differences like this:

export function mapContractTemplate(p: IEntityPerson): IRenamed {

  // create a new object and add the new property
  const renamed = {
    personId: p.person_id
  };

  // blind copy all properties
  for(var key in p) {
     renamed[key]=p[key];
  }

  // delete the unwanted 'old' property
  delete renamed.person_id;
  return renamed;
}

This code keeps the same instance of address. It wasn't clear to me if you needed cloning of this object as well.

Answer 3

well there is no dircet way to do it with destructing in my knowlage. what you can do is

 export function mapContractTemplate(p: IEntityPerson): IRenamed { const clone = JSON.parse(JSON.stringify(p)) // deep clone the object clone.personId = clone.person_id delete clone.person_id; return clone }