Skip to content
Biome
Docs Blog Playground

useNumberNamespace

Diagnostic Category: lint/style/useNumberNamespace

Since: v1.5.0

Sources:

Use the Number properties instead of global ones.

ES2015 moved some globals into the Number properties for consistency.

The rule doesn’t report the globals isFinite and isNan because they have a slightly different behavior to their corresponding Number’s properties Number.isFinite and Number.isNan. You can use the dedicated rules noGlobalIsFinite and noGlobalIsNan to enforce the use of Number.isFinite and Number.isNan.

Examples

Section titled Examples

Invalid

Section titled Invalid
parseInt("1"); // true
code-block.js:1:1 lint/style/useNumberNamespace  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ✖ Use Number.parseInt instead of the equivalent global.
  
  > 1 │ parseInt(“1”); // true
      │ ^^^^^^^^
    2 │ 
  
  ℹ ES2015 moved some globals into the Number namespace for consistency.
  
  ℹ Safe fix: Use Number.parseInt instead.
  
    1   │ - parseInt(“1”);·//·true
      1 │ + Number.parseInt(“1”);·//·true
    2 2 │   
  
parseFloat("1.1"); // true
code-block.js:1:1 lint/style/useNumberNamespace  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ✖ Use Number.parseFloat instead of the equivalent global.
  
  > 1 │ parseFloat(“1.1”); // true
      │ ^^^^^^^^^^
    2 │ 
  
  ℹ ES2015 moved some globals into the Number namespace for consistency.
  
  ℹ Safe fix: Use Number.parseFloat instead.
  
    1   │ - parseFloat(“1.1”);·//·true
      1 │ + Number.parseFloat(“1.1”);·//·true
    2 2 │   
  
NaN; // true
code-block.js:1:1 lint/style/useNumberNamespace  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ✖ Use Number.NaN instead of the equivalent global.
  
  > 1 │ NaN; // true
      │ ^^^
    2 │ 
  
  ℹ ES2015 moved some globals into the Number namespace for consistency.
  
  ℹ Safe fix: Use Number.NaN instead.
  
    1   │ - NaN;·//·true
      1 │ + Number.NaN;·//·true
    2 2 │   
  
Infinity; // true
code-block.js:1:1 lint/style/useNumberNamespace  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ✖ Use Number.POSITIVE_INFINITY instead of the equivalent global.
  
  > 1 │ Infinity; // true
      │ ^^^^^^^^
    2 │ 
  
  ℹ ES2015 moved some globals into the Number namespace for consistency.
  
  ℹ Safe fix: Use Number.POSITIVE_INFINITY instead.
  
    1   │ - Infinity;·//·true
      1 │ + Number.POSITIVE_INFINITY;·//·true
    2 2 │   
  
-Infinity; // true
code-block.js:1:2 lint/style/useNumberNamespace  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ✖ Use Number.NEGATIVE_INFINITY instead of the equivalent global.
  
  > 1 │ -Infinity; // true
      │  ^^^^^^^^
    2 │ 
  
  ℹ ES2015 moved some globals into the Number namespace for consistency.
  
  ℹ Safe fix: Use Number.NEGATIVE_INFINITY instead.
  
    1   │ - -Infinity;·//·true
      1 │ + Number.NEGATIVE_INFINITY;·//·true
    2 2 │

Valid

Section titled Valid
Number.parseInt("1"); // false
Number.parseFloat("1.1"); // false
Number.NaN; // false
Number.POSITIVE_INFINITY; // false
Number.NEGATIVE_INFINITY; // false
Section titled Related links