#max-nested-callbacks

#Configuration

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

export default defineConfig([
  js.configs.recommended,
  {
    rules: {
      'max-nested-callbacks': 'error',
    },
  },
]);

#Rule Details

This rule enforces a maximum depth that callbacks can be nested to improve code readability. A common anti-pattern is "callback hell" — deeply nested callbacks that grow rightward and become hard to follow.

A function expression or arrow function counts toward the nesting depth only when it is passed directly to a call (as a call argument or as the callee of an immediately-invoked call). Function-likes assigned to variables, object or class properties, array elements, JSX attributes, default parameter values, or used as new arguments / tagged-template arguments do not increase the counter.

Examples of incorrect code for this rule with the default { "max": 10 } option:

foo1(function () {
  foo2(function () {
    foo3(function () {
      foo4(function () {
        foo5(function () {
          foo6(function () {
            foo7(function () {
              foo8(function () {
                foo9(function () {
                  foo10(function () {
                    foo11(function () {});
                  });
                });
              });
            });
          });
        });
      });
    });
  });
});

Examples of correct code for this rule with the default { "max": 10 } option:

foo1(handleFoo1);

function handleFoo1() {
  foo2(handleFoo2);
}

function handleFoo2() {
  foo3(handleFoo3);
}

#Options

This rule accepts a number, or an object with the following properties:

• max (default 10): the maximum nesting depth allowed.
• maximum: deprecated alias for max. When both keys are present and maximum is truthy, maximum wins (matching ESLint's option.maximum || option.max coercion).

#max

Examples of incorrect code for this rule with { "max": 3 }:

{ "max-nested-callbacks": ["error", { "max": 3 }] }

foo1(function () {
  foo2(function () {
    foo3(function () {
      foo4(function () {});
    });
  });
});

Examples of correct code for this rule with { "max": 3 }:

{ "max-nested-callbacks": ["error", { "max": 3 }] }

foo1(function () {
  foo2(function () {
    foo3(function () {});
  });
});

Arrow functions are counted the same as function expressions:

foo1(() => {
  foo2(() => {
    foo3(() => {
      foo4(() => {});
    });
  });
});

#Original Documentation

• https://eslint.org/docs/latest/rules/max-nested-callbacks