#unbound-method

#Configuration

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

export default defineConfig([
  ts.configs.recommended,
  {
    rules: {
      '@typescript-eslint/unbound-method': 'error',
    },
  },
]);

#Rule Details

Enforce unbound methods are called with their expected scope. Extracting a class method as a standalone variable or callback without binding it to the class instance causes this to be undefined at runtime, which is a common source of bugs. This rule reports when a method is referenced without being called, unless it is in a safe context (like a comparison, typeof check, or conditional check).

If the method does not access this, the rule additionally suggests annotating the method parameter with this: void or converting it to an arrow function.

Examples of incorrect code for this rule:

class MyClass {
  method() {
    return this.value;
  }
}
const instance = new MyClass();
const unboundMethod = instance.method;
[1, 2, 3].forEach(instance.method);

Examples of correct code for this rule:

class MyClass {
  method() {
    return this.value;
  }
}
const instance = new MyClass();
const boundMethod = instance.method.bind(instance);
instance.method();
if (instance.method) {
}
typeof instance.method;

#Original Documentation

• typescript-eslint unbound-method