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useNumericLiterals (since v1.0.0)

Diagnostic Category: lint/style/useNumericLiterals

Sources:

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

Section titled Examples

Invalid

Section titled Invalid
parseInt("111110111", 2);
style/useNumericLiterals.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);
style/useNumericLiterals.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);
style/useNumericLiterals.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

Section titled 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);
Section titled Related links