Javascript regex for specific name validation

user_12409766 0
Viewed 63

I have a university assignment to write a JS regex for name validation: name can include spaces at the beginning and the end (don't ask anything, it's our teacher demand), also it can include such chars like: -, ' and space (" "). At the moment, my regex looks like that:

var Nameregex = /^( ?)*[A-Z]+((['-])?[a-z]+)*(([ ]?[a-z]*)*)*$/g;

It works almost perfect, but except for one case: one word (words separated from each other with spaces and - symbols) can contain only one ' symbol.

For example, names like John-andrew'andrew'john shouldn't work. But John-andrew'john-andrew'john should work.

javascript regex
1 Answers

Add a (?!.*'[A-Za-z]+') negative lookahead after ^:

/^(?!.*'[A-Za-z]+')\s*[A-Z]+(?:['-]?[a-z]+)*(?:\s*[a-z]*)*$/

See proof

Explanation

--------------------------------------------------------------------------------
  ^                        the beginning of the string
--------------------------------------------------------------------------------
  (?!                      look ahead to see if there is not:
--------------------------------------------------------------------------------
    .*                       any character except \n (0 or more times
                             (matching the most amount possible))
--------------------------------------------------------------------------------
    '                        '\''
--------------------------------------------------------------------------------
    [A-Za-z]+                any character of: 'A' to 'Z', 'a' to 'z'
                             (1 or more times (matching the most
                             amount possible))
--------------------------------------------------------------------------------
    '                        '\''
--------------------------------------------------------------------------------
  )                        end of look-ahead
--------------------------------------------------------------------------------
  \s*                      whitespace (\n, \r, \t, \f, and " ") (0 or
                           more times (matching the most amount
                           possible))
--------------------------------------------------------------------------------
  [A-Z]+                   any character of: 'A' to 'Z' (1 or more
                           times (matching the most amount possible))
--------------------------------------------------------------------------------
  (?:                      group, but do not capture (0 or more times
                           (matching the most amount possible)):
--------------------------------------------------------------------------------
    ['-]?                    any character of: ''', '-' (optional
                             (matching the most amount possible))
--------------------------------------------------------------------------------
    [a-z]+                   any character of: 'a' to 'z' (1 or more
                             times (matching the most amount
                             possible))
--------------------------------------------------------------------------------
  )*                       end of grouping
--------------------------------------------------------------------------------
  (?:                      group, but do not capture (0 or more times
                           (matching the most amount possible)):
--------------------------------------------------------------------------------
    \s*                      whitespace (\n, \r, \t, \f, and " ") (0
                             or more times (matching the most amount
                             possible))
--------------------------------------------------------------------------------
    [a-z]*                   any character of: 'a' to 'z' (0 or more
                             times (matching the most amount
                             possible))
--------------------------------------------------------------------------------
  )*                       end of grouping
--------------------------------------------------------------------------------
  $                        before an optional \n, and the end of the
                           string
user_113298900
Related