useNumericLiterals

Diagnostic Category: lint/style/useNumericLiterals

JavaScript (and super languages)

Since: v1.0.0

Sources:

Same as: prefer-numeric-literals

Description

Disallow parseInt() and Number.parseInt() in favor of binary, octal, and hexadecimal literals

JavaScript provides literal forms for binary, octal, and hexadecimal numbers. For example: 0b11, 0o77, and 0xff. Using the literal forms enable static code analysis and avoid unnecessary computations.

Examples

Invalid

parseInt("111110111", 2);

code-block.js:1:1 lint/style/useNumericLiterals  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ✖ This call to parseInt() can be replaced by a binary literal.
  
  > 1 │ parseInt(“111110111”, 2);
      │ ^^^^^^^^^^^^^^^^^^^^^^^^
    2 │ 
  
  ℹ Using a literal avoids unnecessary computations.
  
  ℹ Unsafe fix: Use the computed binary literal instead.
  
    1   │ - parseInt(“111110111”,·2);
      1 │ + 0b111110111;
    2 2 │

Number.parseInt("767", 8);

code-block.js:1:1 lint/style/useNumericLiterals  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ✖ This call to Number.parseInt() can be replaced by an octal literal.
  
  > 1 │ Number.parseInt(“767”, 8);
      │ ^^^^^^^^^^^^^^^^^^^^^^^^^
    2 │ 
  
  ℹ Using a literal avoids unnecessary computations.
  
  ℹ Unsafe fix: Use the computed octal literal instead.
  
    1   │ - Number.parseInt(“767”,·8);
      1 │ + 0o767;
    2 2 │

Number.parseInt("-1f7", 16);

code-block.js:1:1 lint/style/useNumericLiterals  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ✖ This call to Number.parseInt() can be replaced by a hexadecimal literal.
  
  > 1 │ Number.parseInt(“-1f7”, 16);
      │ ^^^^^^^^^^^^^^^^^^^^^^^^^^^
    2 │ 
  
  ℹ Using a literal avoids unnecessary computations.
  
  ℹ Unsafe fix: Use the computed hexadecimal literal instead.
  
    1   │ - Number.parseInt(“-1f7”,·16);
      1 │ + -0x1f7;
    2 2 │

Valid

parseInt(1);
parseInt(1, 3);
Number.parseInt(1);
Number.parseInt(1, 3);

0b111110111 === 503;
0o767 === 503;
0x1F7 === 503;

a[parseInt](1,2);

parseInt(foo);
parseInt(foo, 2);
Number.parseInt(foo);
Number.parseInt(foo, 2);

How to configure

{
  "linter": {
    "rules": {
      "style": {
        "useNumericLiterals": "error"
      }
    }
  }
}