用于用户名验证的JavaScript正则表达式

Question

I tried with many patters for username in my Angular5 application. But didn't get a suitable solution for my requirement.

The Rules are

Minimum 6 characters
Only numbers are not allowed at least one character should be there
No special characters allowed except _
No space allowed
Character only is allowed

I tried with /^[a-zA-Z0-9]+([_]?[a-zA-Z0-9])*$/

/^[a-zA-Z0-9][a-zA-Z0-9_]*[a-zA-Z0-9](?<![_\s\-]{6,}.*)$/

Answer 1

You can use the following regex:

^(?=[a-z_\d]*[a-z])[a-z_\d]{6,}$

in case insensitive mode as tested on regex101: demo

Explanations:

• ^ anchor for the beginning of the string
• $ anchor for the end of the string
• (?=[a-z_\\d]*[az]) to force the presence of at least one letter
• [a-z_\\d]{6,} implement the at least 6 char constraint

Answer 2

You can try this regex:

^[a-zA-Z0-9_]{5,}[a-zA-Z]+[0-9]*$

• [a-zA-Z0-9_]{5,} to match at least five alphanumerics and the underscore
• [a-zA-Z]+ to have at least one letter
• [0-9]* to match zero to any occurrence of the given numbers range

Hope this helps.

Answer 3

Yes this is fine for me. Thanks. /^[a-zA-Z0-9][a-zA-Z0-9_]*[a-zA-Z0-9](?<![-?\\d+\\.?\\d*$]{6,}.*)$/