#number-literal-case

#Configuration

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

export default defineConfig([
  unicornPlugin.configs.recommended,
  {
    rules: {
      'unicorn/number-literal-case': 'error',
    },
  },
]);

#Rule Details

Enforce lowercase radix prefixes (0x, 0o, and 0b) and a lowercase e in exponential notation. Hexadecimal digits use uppercase by default. The rule checks both numbers and BigInts and provides an automatic fix.

Examples of incorrect code for this rule:

const mask = 0xff;
const flags = 0B1010n;
const permissions = 0O755;
const timeout = 1E3;

Examples of correct code for this rule:

const mask = 0xFF;
const flags = 0b1010n;
const permissions = 0o755;
const timeout = 1e3;

Numeric separators and the lowercase BigInt suffix n are preserved. Strings containing numeric-looking text are not checked.

#Options

#hexadecimalValue

Type: "uppercase" | "lowercase"

Default: "uppercase"

Choose the case of hexadecimal digits. The 0x prefix is always lowercase.

{
  'unicorn/number-literal-case': ['error', { hexadecimalValue: 'lowercase' }]
}

With hexadecimalValue: "lowercase", use 0xff and 0xffn instead of 0xFF and 0xFFn.

#Differences from upstream

Vue single-file components and template expressions are not supported by rslint's parser. For example, this rule does not check {{ 1.2E3 }} inside a Vue template.

The TypeScript parser rejects legacy numeric spellings such as 0777 and 0888 before lint rules run, even in scripts. Upstream accepts these in sloppy-mode JavaScript and leaves them unchanged.

#Original Documentation

• eslint-plugin-unicorn: number-literal-case
• Source code