I have this object:

{
  "id": "Test",
  "firstname": "Test",
  "lastname": "Test",
  "age": 83
}

but i want to return object only with this value:

{
    "id": "Test"
}

how to cast first object to another one with using TS/NodeJS?

CodePudding user response：

You could write a function like this that uses a property accessor to only return the id of the object:

let data = { id: 'Test', firstname: 'Test', lastname: 'Test', age: 83, };

function trimToId(data) {
  return { id: data.id };
}

console.log(trimToId(data))

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If you wanted to make this more concise you could use an arrow function with destructuring:

let data = { id: 'Test', firstname: 'Test', lastname: 'Test', age: 83 };

const trimToId = ({ id }) => ({ id });

console.log(trimToId(data));

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CodePudding user response：

function foo(input) {
   return {id: input.id}; 
}

CodePudding user response：

If your data is just as you presented it:

const object = {
  id: "Test",
  firstname: "Test",
  lastname: "Test",
  age: 83
}

const newObject = {id: object.id}
//or
const {id} = object;//destructuring
const newObject = {id};

CodePudding user response：

I think what you are looking for is a Utility Type called Partial. You can find the documentation here.

interface FirstObject {
  id: string;
  firstname: string;
  lastname: string;
  age: number;
}

const firstObject: FirstObject = {
  "id": "Test",
  "firstname": "Test",
  "lastname": "Test",
  "age": 83
};

const secondObject: Partial<FirstObject> = {
  "_id": "Test"
};

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