TS2790: The operand of a 'delete' operator must be optional

Workarounds

1. 95% success Mark the property as optional in the type definition

   // Before: required property
   interface Config {
     apiKey: string;
     debug: boolean;
   }
   const config: Config = { apiKey: 'abc', debug: true };
   delete config.debug; // TS2790
   
   // After: mark as optional
   interface Config {
     apiKey: string;
     debug?: boolean;  // Now optional
   }
   const config: Config = { apiKey: 'abc', debug: true };
   delete config.debug; // OK

   Sources: https://www.typescriptlang.org/docs/handbook/2/objects.html#optional-properties

2. 92% success Use destructuring with rest to create a new object without the property instead of mutating

   // Instead of deleting, create a new object without the property:
   interface FullUser {
     id: string;
     name: string;
     password: string;
   }
   type SafeUser = Omit<FullUser, 'password'>;
   
   const user: FullUser = { id: '1', name: 'Alice', password: 'secret' };
   // Don't do: delete user.password;
   // Do this instead:
   const { password, ...safeUser }: FullUser = user;
   // safeUser is { id: string; name: string } - type-safe, no mutation
   const result: SafeUser = safeUser;

   Sources: https://www.typescriptlang.org/docs/handbook/variable-declarations.html#object-destructuring

3. 85% success Use Partial<T> for objects where properties may be removed at runtime

   // When the object is expected to have properties removed over its lifetime:
   interface FormFields {
     name: string;
     email: string;
     phone: string;
   }
   
   // Use Partial when the object will be mutated by deleting fields
   const draft: Partial<FormFields> = { name: 'Bob', email: '[email protected]', phone: '555' };
   delete draft.phone; // OK - all properties in Partial are optional
   
   // When you need the full object later, validate:
   function isComplete(f: Partial<FormFields>): f is FormFields {
     return !!f.name && !!f.email && !!f.phone;
   }

   Sources: https://www.typescriptlang.org/docs/handbook/utility-types.html#partialtype