Check if String contains only Latin Letters in JavaScript

Check if String contains only Latin Letters #

To check if a string contains only latin characters, use the test() method with the following regular expression /^[a-zA-Z]+$/. The test method will return true if the string contains only latin characters andfalse otherwise.

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function onlyLatinCharacters(str) {
  return /^[a-zA-Z]+$/.test(str);
}

console.log(onlyLatinCharacters('apple')); // 👉️ true
console.log(onlyLatinCharacters('Buy groceries')); // 👉️ false
console.log(onlyLatinCharacters('pizza,cola')); // 👉️ false

We used the RegExp.test method to check if a string contains only latin characters.

The test method returns true if the string is matched in the regex and false otherwise.

The forward slashes / / mark the start and end of the regular expression.

The caret ^ matches the beginning of the input and the dollar sign $ - the end of the input.

The plus + matches the preceding item (the letter ranges) 1 or more times.

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function onlyLatinCharacters(str) {
  // 👇️ using `i` flag
  return /^[a-z]+$/i.test(str);
}

console.log(onlyLatinCharacters('APPLE')); // 👉️ true

The i flag allows us to do case insensitive search and replaces the uppercase range A-Z.

If you ever need help reading a regular expression, check this regex cheatsheet from MDN out.

If you also need to match dots, commas or spaces, etc, add the character you need to match between the square brackets [].

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function onlyLatinSpacesDots(str) {
  return /^[a-zA-Z\s.,]+$/.test(str);
}

console.log(onlyLatinSpacesDots('apple')); // 👉️ true
console.log(onlyLatinSpacesDots('Buy groceries')); // 👉️ true
console.log(onlyLatinSpacesDots('pizza.cola')); // 👉️ true

In this example we match latin characters, whitespace characters (\s), dots and commas.

You can update this as you need, by adjusting the characters between the square brackets [].

Further Reading #

• Check if a String is all Uppercase in JavaScript
• How to count the words in a String in JavaScript