regex letter code example

Example 1: regex for number and letters

let regex = /[^A-Za-z0-9]+/

Example 2: regex any letter

[a-zA-Z] //all letters
[a-z] //only lowercase letters
[A-Z] //only uppercase letters

Example 3: regex char or char

//check if have "i" or "o"
/i|o/.test(var)