CODEWITHSUNDEEP
reactjstypescript
Faisal Nazik
Faisal Nazik

Reputation: 2863

The operand of a 'delete' operator must be optional.ts(2790) While creating a form using Typescript

I don't understand why this error happening. I'm creating a form to submit user email

export const register = createAsyncThunk<
  User,
  RegisterProps,
  {
    rejectValue: ValidationErrors;
  }
>("auth/registerStatus", async (credentials, { rejectWithValue }) => {
  try {
    // Don't POST blank email
    if (!credentials["email"]) {
      delete credentials["email"]; //editor marking in this line there is error.
    }
    const response = await api.post(API_REGISTER, credentials);
    return response.data;
  } catch (err) {
    const error: AxiosError<ValidationErrors> = err;
    if (!error.response) {
      throw err;
    }
    return rejectWithValue(error.response.data);
  }
});

but I am facing this error:

The operand of a 'delete' operator must be optional.ts(2790)

I guess there is some logic error but I need your help to solve this.

Upvotes: 17

Views: 28871

Answers (5)

E Ciotti
E Ciotti

Reputation: 4955

delete (credentials as any).email

Not very familiar with typescript, but I bumped into something similar and I solved this way

Upvotes: 5

Christiaan Maks
Christiaan Maks

Reputation: 3778

If you want to disable this behavior, set strictNullChecks to false in tsconfig.json:

{
  "compilerOptions": {
    "strictNullChecks": false
  }
}

Upvotes: 1

troy
troy

Reputation: 2515

Another solution, we could use the Partial utility type to construct a new type with the properties set to optional before using the delete operator.

credentials: Partial<Credentials> = { ... };
delete credentials["email"];

Upvotes: 5

Rajitha Udayanga
Rajitha Udayanga

Reputation: 1732

In your credentials interface or class declaration object, you must mark email as option field using ? mark.

ex:

    interface Credentials {
        email?: string,
        ...
    }

Upvotes: 13

Leandro Rocha
Leandro Rocha

Reputation: 351

This error happens because you created a class with the mandatory attribute you can work around creating a mirror class with the optional attributes.

class Foo {
    aa: string
    bb: number
    cc: boolean
}

type FooMirror = {aa: string, bb?: number, cc?: boolean}

const foo = new Foo()

const test: FooMirror = foo

delete test.aa // error operator must by optional
delete test.bb // true
delete test.cc // true

Upvotes: 4

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