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typescript/no-non-null-assertion Restriction

What it does

Disallow non-null assertions using the ! postfix operator.

Why is this bad?

TypeScript's ! non-null assertion operator asserts to the type system that an expression is non-nullable, as in not null or undefined. 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.

Example

ts
x!;
x!.y;
x.y!;

How to use

To enable this rule in the CLI or using the config file, you can use:

bash
oxlint --deny typescript/no-non-null-assertion
json
{
  "rules": {
    "typescript/no-non-null-assertion": "error"
  }
}

References

Released under the MIT License.