#no-non-null-assertion

#Configuration

import { defineConfig, ts } from '@rslint/core';

export default defineConfig([
  ts.configs.recommended,
  {
    rules: {
      '@typescript-eslint/no-non-null-assertion': 'error',
    },
  },
]);

#Rule Details

Disallows non-null assertions using the ! postfix operator.

TypeScript's ! non-null assertion operator asserts to the type system that an expression is non-nullable. Using assertions to tell the type system new information is often a sign that code is not fully type-safe. It's generally better to structure program logic so that TypeScript understands when values may be nullable.

Examples of incorrect code for this rule:

interface Example {
  property?: string;
}
declare const example: Example;
const includesBaz = example.property!.includes('baz');

Examples of correct code for this rule:

interface Example {
  property?: string;
}
declare const example: Example;
const includesBaz = example.property?.includes('baz') ?? false;

#Original Documentation

https://typescript-eslint.io/rules/no-non-null-assertion