typescript/no-unsafe-assignment Pedantic

🚧 An auto-fix is still under development.

What it does

This rule disallows assigning a value with type any to variables and properties.

Why is this bad?

The any type in TypeScript disables type checking and can lead to runtime errors. When you assign an any value to a typed variable, you're essentially bypassing TypeScript's type safety without any guarantees about the actual value.

Examples

Examples of incorrect code for this rule:

declare const anyValue: any;

const str: string = anyValue; // unsafe assignment

let num: number;
num = anyValue; // unsafe assignment

const obj = {
  prop: anyValue as any, // unsafe assignment
};

interface User {
  name: string;
  age: number;
}

const user: User = anyValue; // unsafe assignment

Examples of correct code for this rule:

declare const stringValue: string;
declare const numberValue: number;
declare const unknownValue: unknown;

const str: string = stringValue; // safe

let num: number;
num = numberValue; // safe

// Use type guards with unknown
if (typeof unknownValue === "string") {
  const str2: string = unknownValue; // safe after type guard
}

// Explicit any assignment (still not recommended, but intentional)
const anything: any = unknownValue;

How to use

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

CLI

oxlint --deny typescript/no-unsafe-assignment

Config (.oxlintrc.json)

{
  "rules": {
    "typescript/no-unsafe-assignment": "error"
  }
}

References

• Rule Source