#prefer-catch

#Configuration

import { defineConfig, promisePlugin } from '@rslint/core';

export default defineConfig([
  promisePlugin.configs.recommended,
  {
    rules: {
      'promise/prefer-catch': 'error',
    },
  },
]);

Prefer .catch() over .then(null, fn) or .then(a, b) for error handling.

#Rule Details

A .then() call with two arguments can obscure that an error handler is present. The second argument also only catches rejections from earlier in the chain — not from the first argument — so .catch() is both clearer and semantically preferred.

Examples of incorrect code for this rule:

hey.then(fn1, fn2)
hey.then(null, fn2)
hey.then(undefined, fn2)

Examples of correct code for this rule:

prom.then(fn)
prom.catch(handleErr).then(handle)
prom.catch(handleErr)

#Differences from ESLint

Fixed an upstream autofix bug: x.then(a, b, c) now fixes to x.catch(b).then(a, c) instead of x.catch(b).then(ac).

#Original Documentation

• eslint-plugin-promise: prefer-catch