typescript/no-unsafe-type-assertion Suspicious

🚧 An auto-fix is still under development.

What it does

This rule disallows type assertions using the any type.

Why is this bad?

Type assertions using any completely bypass TypeScript's type system and can lead to runtime errors. They should be avoided in favor of more specific type assertions or proper type guards.

Examples

Examples of incorrect code for this rule:

declare const value: unknown;

const str = value as any; // unsafe type assertion

const obj = value as any as string; // double assertion through any

function processValue(input: unknown) {
  const processed = input as any; // unsafe
  return processed.someProperty;
}

Examples of correct code for this rule:

declare const value: unknown;

// Use specific type assertions
const str = value as string; // more specific assertion

// Use type guards
if (typeof value === "string") {
  const str2 = value; // safe, no assertion needed
}

// Use proper interface assertions
interface User {
  name: string;
  age: number;
}

const user = value as User; // specific type assertion

// Use unknown for truly unknown values
const unknown: unknown = value;

How to use

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

CLI

oxlint --deny typescript/no-unsafe-type-assertion

Config (.oxlintrc.json)

{
  "rules": {
    "typescript/no-unsafe-type-assertion": "error"
  }
}

References

• Rule Source