isAlpha

The isAlpha function checks if a string contains only alphabetic characters (letters), without numbers or symbols.

Syntax

isAlpha(value)

Parameters

Parameter	Type	Description
value	string	The string to be checked.

Return

Type	Description
boolean	Returns true if the string contains only letters, otherwise returns false.

Examples

isAlpha('abc');      // true
isAlpha('ABC');      // true
isAlpha('abc123');   // false
isAlpha('abc!');     // false
isAlpha('áéíóú');    // true
isAlpha('');         // false

Notes

• Throws a TypeError if the provided value is not a string.
• Supports Unicode characters (accents, letters from other alphabets).

References

• MDN: Unicode Property Escapes in Regular Expressions
• MDN: String.prototype.test()