strict-deep-omit

StrictDeepOmit<Type, Filter> constructs a type by picking all properties from type Type and removing properties which values are never or true in type Filter

interface EnglishClass {
  students: { name: string; score: number }[];
  teacher: {
    name: string;
    yearsOfExperience: number;
  };
  year: number;
}

type AnonymousEnglishClass = StrictDeepOmit<
  // ^? { students: { score: number }[]; teacher: { yearsOfExperience: number }; year: number }
  EnglishClass,
  {
    students: { name: never }[];
    teacher: {
      name: never;
    };
  }
>;

It validates that all Filter properties exist in type Type

// error: Type '{ id: never; students: { id: never; }[]; teacher: { id: never; }; }' does not satisfy the constraint '{ students?: true | DeepModify<{ name: string; score: number; }[]> | undefined; teacher?: true | { name?: true | undefined; yearsOfExperience?: true | undefined; } | undefined; year?: true | undefined; }'.
//   Types of property 'students' are incompatible.
//     Type '{ id: never; }[]' is not assignable to type 'true | DeepModify<{ name: string; score: number; }[]> | undefined'.
//       Type '{ id: never; }[]' is not assignable to type '(true | { name?: true | undefined; score?: true | undefined; } | undefined)[]'.
//         Type '{ id: never; }' is not assignable to type 'true | { name?: true | undefined; score?: true | undefined; } | undefined'.
type UnknownEnglishClass = StrictDeepOmit<
  EnglishClass,
  {
    id: never;
    students: { id: never }[];
    teacher: {
      id: never;
    };
  }
  // ^^^^^^^^^^^^^^^^^^^^^^^^
>;

If you don't need a second type parameter Filter to be validated against a structure of a first type parameter Type, please use DeepOmit<Type, Filter>.

Useful in functions which cannot access specified properties

declare const englishClass: EnglishClass;

const takeSurvey = (englishClass: AnonymousEnglishClass) => {
  // Property 'name' does not exist on type '{ yearsOfExperience: number; }'
  englishClass.teacher.name;
  //                   ^^^^
  // Property 'name' does not exist on type '{ score: number; }'
  englishClass.students[0].name;
  //                       ^^^^
};

takeSurvey(englishClass);

⚠️ Limitations:

• StrictDeepOmit cannot be used when Type is generic type – #343 (please use DeepOmit instead)
• (bug) StrictDeepOmit cannot be used on nullable type - #380
• StrictDeepOmit only limits access to specified properties in your codebase, but doesn't remove them in runtime

TS Playground – https://tsplay.dev/wjo7lN