prefer-promise-reject-errors

Require using Error objects as Promise rejection reasons.

🔒

Extending "plugin:@typescript-eslint/strict-type-checked" in an ESLint configuration enables this rule.

💭

This rule requires type information to run.

This rule extends the base eslint/prefer-promise-reject-errors rule. It uses type information to enforce that Promises are only rejected with Error objects.

Examples

❌ Incorrect

Promise.reject('error');

const err = new Error();
Promise.reject('an ' + err);

new Promise((resolve, reject) => reject('error'));

new Promise((resolve, reject) => {
  const err = new Error();
  reject('an ' + err);
});

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✅ Correct

Promise.reject(new Error());

class CustomError extends Error {
  // ...
}
Promise.reject(new CustomError());

new Promise((resolve, reject) => reject(new Error()));

new Promise((resolve, reject) => {
  class CustomError extends Error {
    // ...
  }
  return reject(new CustomError());
});

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Options

See eslint/prefer-promise-reject-errors options.

How to Use

.eslintrc.cjs

module.exports = {
  "rules": {
    // Note: you must disable the base rule as it can report incorrect errors
    "prefer-promise-reject-errors": "off",
    "@typescript-eslint/prefer-promise-reject-errors": "error"
  }
};

Try this rule in the playground ↗

When Not To Use It

Type checked lint rules are more powerful than traditional lint rules, but also require configuring type checked linting. See Performance Troubleshooting if you experience performance degredations after enabling type checked rules.

Resources

• Rule source
• Test source

^{Taken with ❤️ from ESLint core.}