toLower()

toLower(str): string

Converts a string to lowercase.

DEPRECATED

Use string.toLowerCase() directly instead.

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Parameters

str: string | null | undefined

The string to convert to lowercase.

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Returns: string

The string converted to lowercase.

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See Also

• String.toLowerCase() - MDN
• Browser support - Can I Use

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Since

2.0.0

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Also known as

toLower (Lodash, es-toolkit, Ramda) · toLowerCase (Remeda, Effect) · ❌ (Radashi, Modern Dash, Antfu)

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Example

// ❌ Deprecated approach
toLower('HELLO WORLD'); // => 'hello world'

// ✅ Recommended approach
'HELLO WORLD'.toLowerCase(); // => 'hello world'

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How it works?

Converts string to lowercase. Deprecated: Use string.toLowerCase() directly.

Native Equivalent

// ❌ toLower('HELLO')
// ✅ 'HELLO'.toLowerCase()

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Use Cases

Convert to lowercase 📌

Convert string to lowercase.

#lowercase#string#convert#case

'HELLO'.toLowerCase();  // 'hello'

Normalize for comparison

Case-insensitive string comparison.

#normalize#compare#case-insensitive

const matches = input.toLowerCase() === expected.toLowerCase();