Borislav Hadzhiev
Thu Oct 21 2021·2 min read
Photo by Jordan Whitt
To check if a string contains only latin characters, use the test()
method
with the following regular expression /^[a-zA-Z]+$/
. The test
method will
return true
if the string contains only latin characters andfalse
otherwise.
function onlyLatinCharacters(str) { return /^[a-zA-Z]+$/.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.
[]
is called a character class and matches a range of lowercase a-z
and uppercase A-Z
letters.The plus +
matches the preceding item (the letter ranges) 1 or more times.
i
flag to make the regular expression case insensitive. This would allow you to remove the uppercase range A-Z
from the square brackets.function onlyLatinCharacters(str) { // 👇️ using `i` flag return /^[a-z]+$/i.test(str); } console.log(onlyLatinCharacters('APPLE')); // 👉️ true
The i
flag allows us to do case insensitive search and replaces the uppercase
range A-Z
.
If you ever need help reading a regular expression, check this regex cheatsheet from MDN out.
If you also need to match dots, commas or spaces, etc, add the character you
need to match between the square brackets []
.
function onlyLatinSpacesDots(str) { return /^[a-zA-Z\s.,]+$/.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.
\s
special character matches spaces, tabs and new lines.You can update this as you need, by adjusting the characters between the
square brackets []
.