How to check if a string contains at least one letter using regular expression (regex) in JavaScript?

Published February 12, 2021

To check if a string contains at least one letter using regex, you can use the [a-zA-Z] regular expression sequence in JavaScript.

  • The [a-zA-Z] sequence is to match all the small letters from a-z and also the capital letters from A-Z. This should be inside a square bracket to define it as a range.
// Check if string contain atleast one letter 🔥
/[a-zA-Z]/.test("12345hello6789!"); // true

To get a more in-depth explanation of the process. Read on 📖.

Consider we have a string with some letters 12345hello6789! like this,

// String with some letters
const str = "12345hello6789!";

Now let's write the regex by wrapping the [a-zA-Z] sequence range inside regular expression delimiters like this /[a-zA-Z]/.

// String with some letters
const str = "12345hello6789!";

// Regular expression
const regex = /[a-zA-Z]/;

At last, we can use the test() method in the regular expression and pass the string as an argument to the method to test if the string contains at least one letter. It can be done like this,

// String with some letters
const str = "12345hello6789!";

// Regular expression
const regex = /[a-zA-Z]/;

// Check if string contians letters
const doesItHaveLetter = regex.test(str);

console.log(doesItHaveLetter); // true
  • The method returns boolean true if present and false if not.

See the example live in JSBin.

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