Regular Expressions (Regex)

From the example displayed, I introduce the custom regular expression, there is no limitation on regex itself and you can even use the pipe " | " within it and not being scared of interfering with the other validation filters BUT you have to follow a specific pattern (a writing pattern that is), and if you don't, well it will simply fail. Let's explain how it works...

Regex validation is divided in 4 specific parts (Step #1-4).

Let's use the previous Examples #6 and extract the information out of it to see how it works. Step #1-4 are for explanation only, at the end we show the full regex (make sure there is no spaces).

1. Start & end the filter with the following regex: :regex which tells the directive where to extract it.

2. Custom error message YYWW (what do we want to display to the user, it will be appended to INVALID_PATTERN, please refer to the translation file. For example in English it will display the following: Must be following this format: YYWW)

3. Followed by a separator which basically says... after := separator comes the regex pattern

4. Custom regex pattern ^(0[9]|1[0-9]|2[0-9]|3[0-9])(5[0-2]|[0-4][0-9])$

Final code (without spaces):

regex:YYWW:=^(0[9]|1[0-9]|2[0-9]|3[0-9])(5[0-2]|[0-4][0-9])$:regex

###Important note on Regexp Angular-Validation uses in the background RegExp constructor with the first argument defined as a string and there is a very important information to know about this and as mentioned from the great documentation of Mozilla MDN - RegExp Wiki

When using the constructor function, the normal string escape rules (preceding special characters with \ when included in a string) are necessary.

######Example

// pattern accepting 2 separate words
var pattern = /(\w+)\s(\w+)/;

// converting to a string and escaping it will be instead
var pattern = "(\\w+)\\s(\\w+)";
var re = new RegExp(pattern);

######Test your RegExp before adding it to Angular-Validation To be sure of your regular expression, you could test it prior to add it as a validation

// pattern accepting 2 separate words (for example a person full name)
var regex = new RegExp("(\\w+)\\s(\\w+)");
var result1 = regex.test("John Smith");   // will return True
var result2 = regex.test("JohnSmith");    // will return False