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