useNumberNamespace

import { Tabs, TabItem } from '@astrojs/starlight/components';

<Tabs> <TabItem label="JavaScript (and super languages)" icon="seti:javascript"> ## Summary - Rule available since: `v1.5.0` - Diagnostic Category: [`lint/style/useNumberNamespace`](/reference/diagnostics#diagnostic-category) - This rule isn't recommended, so you need to enable it. - This rule has a [**safe**](/linter/#safe-fixes) fix. - The default severity of this rule is [**information**](/reference/diagnostics#information). - Sources: - Same as [`unicorn/prefer-number-properties`](https://github.com/sindresorhus/eslint-plugin-unicorn/blob/main/docs/rules/prefer-number-properties.md)

How to configure

json

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

Description

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

Invalid

parseInt("1"); // true

<pre class="language-text"><code class="language-text">code-block.js:1:1 <a href="https://biomejs.dev/linter/rules/use-number-namespace">lint/style/useNumberNamespace</a> FIXABLE ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ ℹ 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 │ </code></pre>

parseFloat("1.1"); // true

<pre class="language-text"><code class="language-text">code-block.js:1:1 <a href="https://biomejs.dev/linter/rules/use-number-namespace">lint/style/useNumberNamespace</a> FIXABLE ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ ℹ 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 │ </code></pre>

NaN; // true

Infinity; // true

<pre class="language-text"><code class="language-text">code-block.js:1:1 <a href="https://biomejs.dev/linter/rules/use-number-namespace">lint/style/useNumberNamespace</a> FIXABLE ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ ℹ 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 │ </code></pre>

-Infinity; // true

<pre class="language-text"><code class="language-text">code-block.js:1:2 <a href="https://biomejs.dev/linter/rules/use-number-namespace">lint/style/useNumberNamespace</a> FIXABLE ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ ℹ 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 │ </code></pre>

Valid

Number.parseInt("1"); // false

Number.parseFloat("1.1"); // false

Number.NaN; // false

Number.POSITIVE_INFINITY; // false

Number.NEGATIVE_INFINITY; // false

</TabItem> </Tabs>

How to configure

Description

Examples

Invalid

Valid

Related links