ng-pattern to allow alpha and certain special characters

Question

In form - name field I want to do a validation against

• Should allow only Alpha characters
• Allow space
• Allow certain special characters - _ \ / - . ’

I tried,

 ng-pattern="/^[a-z]+[_+\+/+-+.+’][a-z]*$/"

Looks like I have missed out something as its not working!

Solution 1

Let's see:

• Should allow only Alpha characters => [a-zA-Z]
• Allow space => [ ] or \s
• Allow certain special characters - _ \ / - . ’ ' => [_\\\/.’'-]

So, combining all that, the pattern will look like:

ng-pattern="/^[a-zA-Z _\\\/.’'-]+$/"

This matches 1 or more (+) chars from the allowed set.

To disallow leading/trailing whitespace, use

ng-pattern="/^[a-zA-Z_\\\/.’'-]+(?: +[A-Za-z_\\\/.’'-]+)*$/" ng-trim="false"

See the regex demo

The ng-trim="false" will prevent from trimming the input sent to the regex engine. The new regex will match:

• ^ - start of string
• [a-zA-Z_\\\/.’'-]+ - 1 or more letters or allowed symbols other than space
• (?: +[A-Za-z_\\\/.’'-]+)* - zero or more sequences of:
  • + - (or, \s+) - 1 or more spaces (whitespaces)
  • [A-Za-z_\\\/.’'-]+ - see above
• $ - end of string.

Solution 2

/^([a-z _\/.'-])+$/i would do. If you want any space character instead of just space, use /(^[a-z_\/.'-]|\s)+$/i.

Comments

[monda]

It failed for name - Dinesh D'Soza

[Wiktor Stribiżew]

Then just add the single quote to the character class. Just keep in mind that the hyphen must be at the end, right before ].

[Wiktor Stribiżew]

Your regex will match more than you think. See Why is this regex allowing a caret?

[monda]

Can we restrict leading/trailing whitespace ?

[Wiktor Stribiżew]

So, the requirement changed ? :) Yes, it is easy.