#no-eq-null

#Configuration

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

export default defineConfig([
  js.configs.recommended,
  {
    rules: {
      'no-eq-null': 'error',
    },
  },
]);

#Rule Details

Comparing to null without a type-checking operator (== or !=) can have unintended results as the comparison will evaluate to true when comparing not just to null, but also to undefined.

The no-eq-null rule aims to reduce potential bugs and unwanted behavior by ensuring that comparisons to null only match null, and not also undefined. As such, it will flag comparisons to null when using == and !=.

Examples of incorrect code for this rule:

if (foo == null) {
  bar();
}

while (qux != null) {
  baz();
}

Examples of correct code for this rule:

if (foo === null) {
  bar();
}

while (qux !== null) {
  baz();
}

#Original Documentation

• ESLint: no-eq-null
• Source code