1-> You can use "|" operator in between two differebt regex expression 
2in php for selection of any one of them
3
4-> Example for Php only
5  [a-z]|[0-9] patteren will select either small alphabet or numbers from 
6  a string

1Grouping Operators (( ... ) or \( ... \))

1/[]/
2
3
4let bigStr = "big";
5let bagStr = "bag";
6let bugStr = "bug";
7let bogStr = "bog";
8let bgRegex = /b[aiu]g/;
9bigStr.match(bgRegex);
10bagStr.match(bgRegex);
11bugStr.match(bgRegex);
12bogStr.match(bgRegex);