javascript regex to require at least one special character - javascript

I've seen plenty of regex examples that will not allow any special characters. I need one that requires at least one special character.
I'm looking at a C# regex
var regexItem = new Regex("^[a-zA-Z0-9 ]*$");
Can this be converted to use with javascript? Do I need to escape any of the characters?
Based an example I have built this so far:
var regex = "^[a-zA-Z0-9 ]*$";
//Must have one special character
if (regex.exec(resetPassword)) {
isValid = false;
$('#vsResetPassword').append('Password must contain at least 1 special character.');
}
Can someone please identify my error, or guide me down a more efficient path? The error I'm currently getting is that regex has no 'exec' method

Your problem is that "^[a-zA-Z0-9 ]*$" is a string, and you need a regex:
var regex = /^[a-zA-Z0-9 ]*$/; // one way
var regex = new RegExp("^[a-zA-Z0-9 ]*$"); // another way
[more information]
Other than that, your code looks fine.

In javascript, regexs are formatted like this:
/^[a-zA-Z0-9 ]*$/
Note that there are no quotation marks and instead you use forward slashes at the beginning and end.

In javascript, you can create a regular expression object two ways.
1) You can use the constructor method with the RegExp object (note the different spelling than what you were using):
var regexItem = new RegExp("^[a-zA-Z0-9 ]*$");
2) You can use the literal syntax built into the language:
var regexItem = /^[a-zA-Z0-9 ]*$/;
The advantage of the second is that you only have to escape a forward slash, you don't have to worry about quotes. The advantage of the first is that you can programmatically construct a string from various parts and then pass it to the RegExp constructor.
Further, the optional flags for the regular expression are passed like this in the two forms:
var regexItem = new RegExp("^[A-Z0-9 ]*$", "i");
var regexItem = /^[A-Z0-9 ]*$/i;
In javascript, it seems to be a more common convention to the user /regex/ method that is built into the parser unless you are dynamically constructing a string or the flags.

Related

Turning a regex returned as a string from an API into a valid RegEx object in JavaScript

I'm fetching a regular expression from an external API, and it comes back as a string. I want to use the regex for address validation, but I can't seem to properly escape the unwanted characters after calling new RegExp() on the string.
Here's the regex I want to use:
console.log(regexFromAPI);
Output
/((\W|^)box\s+(#\s*)?\d+|post\s+office|(\W|^)p\.?\s*o\.?\s+(#\s*)?\d+)/i
However, I can't use that -- I need it to actually be a regex first.
If I do, for example:
const pattern = new RegExp(regexFromAPI);
and then:
console.log(pattern);
I get the following:
Output
//((W|^)boxs+(#s*)?d+|posts+office|(W|^)p.?s*o.?s+(#s*)?d+)/i/
My question is... why is this happening, and how can I avoid it? I want to use my string literal as a regex.
Thanks in advance.
The RegExp constructor does not expect a string with / delimiters, nor with options past the final /. If you do that, the pattern generated from calling new RegExp with it will result in one that matches a string which starts with a literal forward slash /, and ends with a forward slash / followed by the flag characters (here, i).
Instead, you should pass the pattern string without / delimiters, and pass the flags as the second argument - you can extract these easily by using another regular expression:
const fullPatternStr = String.raw`/((\W|^)box\s+(#\s*)?\d+|post\s+office|(\W|^)p\.?\s*o\.?\s+(#\s*)?\d+)/i`;
const [, pattern, flags] = fullPatternStr.match(/\/(.*)\/([a-z]*)/);
const regex = new RegExp(pattern, flags);
console.log(regex);
Take off the slashes and flags, then reconstruct it:
const str = String.raw`/((\W|^)box\s+(#\s*)?\d+|post\s+office|(\W|^)p\.?\s*o\.?\s+(#\s*)?\d+)/i`;
let regexBody = str.slice(1, str.lastIndexOf("/"));
let flags = str.split("/")[str.split("/").length - 1];
let regex = new RegExp(regexBody, flags);
console.log(regex);

regex for serial number in javascript

var serialNumber = $('#SerialNumber').val();
var serialNumberPattern = new RegExp('^[\s\da-zA-z\-.]+$');
if (!serialNumberPattern.test(serialNumber)) {
}
Above is the code I am using to validate a serial number which has alphanumeric characters, dots (.), dashes (-), and slashes (/) in it but somehow it's not working. Where am I going wrong? Please help.
When you're passing regex to RegExp constructor which uses " as regex delimiter, you have to escape all the backslashes one more time. Or otherwise it would be treated as an escape sequence.
var serialNumberPattern = new RegExp("^[\\s\\da-zA-Z.-]+$");
alphanumeric,dot(.),Dash(-),Slash(/) in it.
var serialNumberPattern = new RegExp("^[\\da-zA-Z./-]+$");
Just use /^[\s\da-zA-Z\-.\/]+$/, it's simple and works just fine.
You should only use the RegExp constructor when parts of the expression use a variable. This is not true in your case and just adds additional confusion.
document.write(/^[\s\da-zA-Z\-.\/]+$/.test('23 43-89'))

Firefox Extension How to pass string type variable into javascript replace regex parameter?

I've been working on firefox extension for several days now and there is one thing I can't solve.
I generate a list of regex and I wanted to pass that string into replace function in javascript (in the regex parameters). Here is the example of the string:
/(https?:\/\/(www\.)?rapidgator\.net\b([-a-zA-Z0-9#:%_\+.~#?&//=]*))/g
/(https?:\/\/(www\.)?ul\.to\b([-a-zA-Z0-9#:%_\+.~#?&//=]*))/g
/(https?:\/\/(www\.)?uploadable\.ch\b([-a-zA-Z0-9#:%_\+.~#?&//=]*))/g
/(https?:\/\/(www\.)?180upload\.com\b([-a-zA-Z0-9#:%_\+.~#?&//=]*))/g
For a convenient way, lets make it this way. I managed to get the file and get the first line of the string and assign it into a variable:
var rapidgator = "/(https?:\/\/(www\.)?rapidgator\.net\b([-a-zA-Z0-9#:%_\+.~#?&//=]*))/g";
I want the string to be a "replace parameter" like this:
var rep = rep.replace(rapidgator,"<a href='$1'>$1</a>");
But I cant get that work.
I've been trying to use RegExp object and that didn't work to.
var rapidgator = new RegExp("(https?:\/\/(www\.)?rapidgator\.net\b([-a-zA-Z0-9#:%_\+.~#?&//=]*))", "g");
How to make that work? Thank you for your advice :)
If you can get the regex, why not let it remain a regex literal?
var rapidgator = /(https?:\/\/(www\.)?rapidgator\.net\b([-a-zA-Z0-9#:%_\+.~#?&//=]*))/g;
If you want to make it through RegExp constructor, make sure you escape \ with another backslash and you don't need delimiters and the second argument takes the flags.
As in
var rapidgator = new RegExp("(https?:\\/\\/(www\\.)?rapidgator\\.net\\b([-a-zA-Z0-9#:%_\+.~#?&//=]*))","g")
You need to escape the backslash one more time when passing your regex within double quotes.
var rapidgator = new RegExp("(https?://(www\\.)?rapidgator\\.net\\b([-a-zA-Z0-9#:%_\\\\+.~#?&/=]*))", "g");
And also to match a backslash, you need to escape it exactly three times.

RegExp.test not working?

I am trying to validate year using Regex.test in javascript, but no able to figure out why its returning false.
var regEx = new RegExp("^(19|20)[\d]{2,2}$");
regEx.test(inputValue) returns false for input value 1981, 2007
Thanks
As you're creating a RegExp object using a string expression, you need to double the backslashes so they escape properly. Also [\d]{2,2} can be simplified to \d\d:
var regEx = new RegExp("^(19|20)\\d\\d$");
Or better yet use a regex literal to avoid doubling backslashes:
var regEx = /^(19|20)\d\d$/;
Found the REAL issue:
Change your declaration to remove quotes:
var regEx = new RegExp(/^(19|20)[\d]{2,2}$/);
Do you mean
var inputValue = "1981, 2007";
If so, this will fail because the pattern is not matched due to the start string (^) and end string ($) characters.
If you want to capture both years, remove these characters from your pattern and do a global match (with /g)
var regEx = new RegExp(/(?:19|20)\d{2}/g);
var inputValue = "1981, 2007";
var matches = inputValue.match(regEx);
matches will be an array containing all matches.
I've noticed, for reasons I can't explain, sometimes you have to have two \\ in front of the d.
so try [\\d] and see if that helps.

Split string in JavaScript using a regular expression

I'm trying to write a regex for use in javascript.
var script = "function onclick() {loadArea('areaog_og_group_og_consumedservice', '\x26roleOrd\x3d1');}";
var match = new RegExp("'[^']*(\\.[^']*)*'").exec(script);
I would like split to contain two elements:
match[0] == "'areaog_og_group_og_consumedservice'";
match[1] == "'\x26roleOrd\x3d1'";
This regex matches correctly when testing it at gskinner.com/RegExr/ but it does not work in my Javascript. This issue can be replicated by testing ir here http://www.regextester.com/.
I need the solution to work with Internet Explorer 6 and above.
Can any regex guru's help?
Judging by your regex, it looks like you're trying to match a single-quoted string that may contain escaped quotes. The correct form of that regex is:
'[^'\\]*(?:\\.[^'\\]*)*'
(If you don't need to allow for escaped quotes, /'[^']*'/ is all you need.) You also have to set the g flag if you want to get both strings. Here's the regex in its regex-literal form:
/'[^'\\]*(?:\\.[^'\\]*)*'/g
If you use the RegExp constructor instead of a regex literal, you have to double-escape the backslashes: once for the string literal and once for the regex. You also have to pass the flags (g, i, m) as a separate parameter:
var rgx = new RegExp("'[^'\\\\]*(?:\\\\.[^'\\\\]*)*'", "g");
while (result = rgx.exec(script))
print(result[0]);
The regex you're looking for is .*?('[^']*')\s*,\s*('[^']*'). The catch here is that, as usual, match[0] is the entire matched text (this is very normal) so it's not particularly useful to you. match[1] and match[2] are the two matches you're looking for.
var script = "function onclick() {loadArea('areaog_og_group_og_consumedservice', '\x26roleOrd\x3d1');}";
var parameters = /.*?('[^']*')\s*,\s*('[^']*')/.exec(script);
alert("you've done: loadArea("+parameters[1]+", "+parameters[2]+");");
The only issue I have with this is that it's somewhat inflexible. You might want to spend a little time to match function calls with 2 or 3 parameters?
EDIT
In response to you're request, here is the regex to match 1,2,3,...,n parameters. If you notice, I used a non-capturing group (the (?: ) part) to find many instances of the comma followed by the second parameter.
/.*?('[^']*')(?:\s*,\s*('[^']*'))*/
Maybe this:
'([^']*)'\s*,\s*'([^']*)'

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