using regex set in javascript object property

Question

I have to use regular expression which is set in javascript's object property, like below

var myObj = { mask : /([a-z]|[A-Z]|[0-9]|-|\.|\'|[&])/}

in some other function which will get myObj as parameter and in that function I need to test that if string contains any character not matching above regex. Example

function check(myObj , value){
//Want to code here to read myObj.mask and return false if value contains 
//any character not matching myObj.mask. as per above example if value contain any special character 
// like &#$% then i want to return false

}

Questions asking for code must demonstrate a minimal understanding of the problem being solved. Include attempted solutions, why they didn't work, and the expected results. — Stewie
– Stewie, Commented Mar 2, 2014 at 9:43

acdcjunior · Accepted Answer · 2013-08-02 05:12:44Z

2

Your regex is very redundant, you are doing lots of unnecessary escaping. You can use the shorter version:

/^([a-zA-Z0-9-.'&])*$/

Notice I added some anchors, they are necessary for RegExp.test();

var myObj = { mask : /^([a-zA-Z0-9-.'&])*$/ }

function check(myObj , value){
    return myObj.mask.test(value);
}

console.log(check(myObj, "abc1-.'&")); //true
console.log(check(myObj, "&#$%")); //false
console.log(check(myObj, "abc#")); //false

Explanation for `/^([a-zA-Z0-9-.'&])*$/`

^ the beginning of the string
( group and capture start group 1
[a-zA-Z0-9-.'&] any character of: a to z, A to Z, 0 to 9, -, ., ' or &
) end of group 1
* group 1 zero or more times
$ end of the string

It is simpler than the original because [a-z]|[A-Z] is the same as [a-zA-Z]. Also, inside character classes (that is, between [ and ]), you don't have to escape ., ' or &.

If you can't change the expression

In that case, we can create a new RegExp object, adapting the one passed as parameter.

var myObj = { mask : /([a-z]|[A-Z]|[0-9]|-|\.|\'|[&])/ }

function check(myObj , value){
    return new RegExp('^'+myObj.mask.source+'*$').test(value);
}

console.log(check(myObj, "abc1-.'&")); // true
console.log(check(myObj, "&#$%")); // false
console.log(check(myObj, "abc#")); // false

edited Aug 2, 2013 at 5:12

answered Aug 2, 2013 at 4:38

acdcjunior

136k37 gold badges340 silver badges312 bronze badges

Sign up to request clarification or add additional context in comments.

10 Comments

Praveen Over a year ago

Would like to know a short explanation of your regex /^([a-zA-Z0-9-.'&])*$/

user2587132 Over a year ago

one doubt, what if ? is used instead * will that not be okay?

acdcjunior Over a year ago

@user1671639 I added some explanation. Can you check if it good enough?

Mics Over a year ago

return new RegExp('^(' + myObj.mask.source + ')*$').test(value);

acdcjunior Over a year ago

@rps With ? it will match nothing, so I guess it is not ok. Check this test: jsfiddle.net/acdcjunior/QFuxt/1 (open console F12). The () is necessary when you want to choose who the * or ? will affect. They also form groups, accessible through $1. No need to be sorry. Feel free to ask. If I can help, I gladly will.

|

SoWhat · Accepted Answer · 2013-08-02 04:36:10Z

0

This can be done by

return myObj.mask.test(value)

answered Aug 2, 2013 at 4:36

SoWhat

5,6222 gold badges30 silver badges63 bronze badges

3 Comments

Mics Over a year ago

I think it's wrong answer(either @user1671639's too). OP wants to test that "if string contains any character not matching above regex". So 'abcd#' should be false since it contains '#'.

sagar Over a year ago

Thanks for response, but if value contains even one special character like $%^#, then will it return false?

SoWhat Over a year ago

yes Sagar it will. I am assuming u want abc# to return false. That's exactly what it will do. abc will return true. I am only telling u how to test a regex, not reformatting it

Collectives™ on Stack Overflow

using regex set in javascript object property

2 Answers 2

Explanation for `/^([a-zA-Z0-9-.'&])*$/`

If you can't change the expression

10 Comments

3 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Explanation for /^([a-zA-Z0-9-.'&])*$/

If you can't change the expression

10 Comments

3 Comments

Your Answer

Sign up or log in

Post as a guest

Related

Explanation for `/^([a-zA-Z0-9-.'&])*$/`