Remove fields from typescript interface object

user_1020120 0
Viewed 15371

I am getting a json response and storing it in mongodb, however the fields that I don't need are also getting in to the database, is there anyway to strip the uneseccary fields?

interface Test{
    name:string
};
const temp :Test = JSON.parse('{ "name":"someName","age":20 }') as Test;
console.log(temp);

output :

{ name: 'someName', age: 20 }
typescript json javascript
4 Answers

If you want to do this in a strongly-typed way, you can define a dummy/ideal object which satisfies your interface (const dummy: IMyInterface = {someField: "someVal"};), and then filter incoming objects' fields against Object.keys(dummy). This way your compiler will complain if you update the interface without updating this 'filtering' code.

user_9706730

Let say you have this object.

const x = {a: 1, b: 2, c: 3};

If you want to make a object with only a and b, you can use the following method.

const {c, ...y} = x;
console.log(y);

You will see that y has only a and b now.
Also this will not give an error if the field c was not in x. As an example,

const x: any = {a: 1, b: 2, c: 3};
const {d, ...y} = x;
console.log(y);

This works perfectly fine without any error and if you log the value of d, it will be undefined.

user_29243230
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