StrictExclude<BaseType, ExcludedMembers>

Overview

This type is a stricter version of TypeScript's Exclude utility type.

Unlike Exclude, which allows excluded members not present on the given type, StrictExclude ensures that only members actually present in the type can be excluded.

Syntax

type StrictExclude<BaseType, ExcludedMembers extends BaseType> = Exclude<
  BaseType,
  ExcludedMembers
>;

• BaseType: The type from which you want to exclude union members.
• ExcludedMembers: The members or types that you want to exclude from BaseType.

Examples

Example #1

type Example = 'admin' | 'editor' | 'viewer';
type StrictExcludedExample = StrictExclude<Example, 'admin'>;
// Result: "editor" | "viewer"

TIP

If your team is using ESLint and wants to enforce the use of StrictExclude instead of the standard Exclude, you can configure ESLint to help catch this. The @typescript-eslint/ban-types rule can be configured to display an error message when Exclude is used, guiding developers to use StrictExclude instead. Here's how you can set up your ESLint configuration:

module.exports = {
  parser: '@typescript-eslint/parser',
  plugins: ['@typescript-eslint'],
  rules: {
    // Include other relevant rules here
    '@typescript-eslint/ban-types': [
      'error',
      {
        types: {
          Exclude: 'Use StrictExclude instead',
        },
        extendsDefaults: true,
      },
    ],
  },
};