typescript/prefer-promise-reject-errors Pedantic

🚧 An auto-fix is still under development.

What it does

This rule enforces passing an Error object to Promise.reject().

Why is this bad?

It's considered good practice to only reject promises with Error objects. This is because Error objects automatically capture a stack trace, which is useful for debugging. Additionally, some tools and environments expect rejection reasons to be Error objects.

Examples

Examples of incorrect code for this rule:

Promise.reject("error"); // rejecting with string

Promise.reject(42); // rejecting with number

Promise.reject(true); // rejecting with boolean

Promise.reject({ message: "error" }); // rejecting with plain object

Promise.reject(null); // rejecting with null

Promise.reject(); // rejecting with undefined

const error = "Something went wrong";
Promise.reject(error); // rejecting with non-Error variable

Examples of correct code for this rule:

Promise.reject(new Error("Something went wrong"));

Promise.reject(new TypeError("Invalid type"));

Promise.reject(new RangeError("Value out of range"));

// Custom Error subclasses
class CustomError extends Error {
  constructor(message: string) {
    super(message);
    this.name = "CustomError";
  }
}
Promise.reject(new CustomError("Custom error occurred"));

// Variables that are Error objects
const error = new Error("Error message");
Promise.reject(error);

How to use

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

CLI

oxlint --deny typescript/prefer-promise-reject-errors

Config (.oxlintrc.json)

{
  "rules": {
    "typescript/prefer-promise-reject-errors": "error"
  }
}

References

• Rule Source