Regex to check for at least 3 characters?

Question

I have this regex to allow for only alphanumeric characters.

How can I check that the string at least contains 3 alphabet characters as well.

My current regex,

if(!/^[a-zA-Z0-9]+$/.test(val)) 

I want to enforce the string to make sure there is at least 3 consecutive alphabet characters as well so;

111 // false aaa1 // true 11a // false bbc // true 1a1aa // false 

Answer 1

To enforce three alphabet characters anywhere,

/(.*[a-z]){3}/i 

should be sufficient.

Edit. Ah, you'ved edited your question to say the three alphabet characters must be consecutive. I also see that you may want to enforce that all characters should match one of your "accepted" characters. Then, a lookahead may be the cleanest solution:

/^(?.*[a-z]{3})[a-z0-9]+$/i 

Note that I am using the case-insensitive modifier /i in order to avoid having to write a-zA-Z.

Alternative. You can read more about lookaround assertions here. But it may be a little bit over your head at this stage. Here's an alternative that you may find easier to break down in terms of what you already know:

/^([a-z0-9]*[a-z]){3}[a-z0-9]*$/i 

Answer 2

+ means "1 or more occurrences."

{3} means "3 occurrences."

{3,} means "3 or more occurrences."

+ can also be written as {1,}.

* can also be written as {0,}.