Develop Reference

JavaScript regex.exec() should intended to use an assembled regEx

if I use ( https://jsfiddle.net/fgsvzn4a/ ) :
var text = "ui1pu";
var regExParameter = '\d+';
var regEx = '/(.*)' + regExParameter + '(.*)/gi';
var matches = regEx.exec(text);
if(matches && matches[1]) {
var str1 = matches[1];
var str2 = matches[2];
var newStr = str1 + str2
console.log(newStr);
}
i get this error:
Paused on exception
TypeError: regEx.exec is not a function
this prototype is working (inspired by https://stackoverflow.com/a/15845184/2891692 ):
var text = "my1bla";
var matches = /(my)\d+(.*)/gi.exec(text);
if(matches && matches[1]) {
var str1 = matches[1];
var str2 = matches[2];
var newStr = str1 + str2
alert(newStr);
}
but i want to use input parameters to build the regex (first example).
i get ReferenceError: Regex is not defined if i try this:
var text = "ui1pu";
var regExParameter = '\d+';
var regExString = '/(.*)' + regExParameter + '(.*)/gi';
var regEx = new Regex(regExString);
var matches = regEx.exec(text);
if(matches && matches[1]) {
var str1 = matches[1];
var str2 = matches[2];
var newStr = str1 + str2
console.log(newStr);
}
any idea?

Use the RegExp constructor. Note that the slashes should be omitted from the string and the flags should be passed as the second argument.
var text = "ui1pu";
var regExParameter = '\\d+';
var regExString = '(.*)' + regExParameter + '(.*)';
var regEx = new RegExp(regExString, 'gi');
var matches = regEx.exec(text);
if(matches && matches[1]) {
var str1 = matches[1];
var str2 = matches[2];
var newStr = str1 + str2
console.log(newStr);
}

Based on the previous correct answers, I was able to come up with this more comprehensive solution. Its a little modification of this correct answer by Unmitigated and all answers :
// window.replaceDOM = function (regExParameter, replaceParameter) {
function replaceDOM(regExParameter, replaceParameter) {
// let reg = '/' + search + '/';
// regExParameter = '\\d+';
console.log('regExParameter=' + regExParameter);
const regExString = '(\\w+)' + regExParameter + '(\\w+)'; // ugly but needet. that escape, that double backslash
console.log('regExString=' + regExString);
const regEx = new RegExp(regExString, 'gi');
let elems = document.body.getElementsByTagName("*");
for (i in elems) {
let ele = elems[i];
if(ele.classList){
const val = ele.classList.value;
if(!val)
continue;
const matches = regEx.exec(val);
if(matches && matches[1]) {
console.log('val=' + val);
const str1 = matches[1];
const str2 = matches[2];
const valNew = str1 + replaceParameter + str2
// alert(valNew);
console.log('valNew=' + valNew);
ele.classList.value = ele.classList.value.replace(val, valNew);
}
}
};
}
.my1bla {
background-color: black;
}
.mybla {
background-color: blue;
}
<button onclick="replaceDOM('y\\d+','y')">
change the style class from DIV using regEx</button>
<div class="my1bla">
I am a DIV element
</div>

node.js replace() - Invalid string length error

I've just coded a little script to replace all variables from a .txt file to their values in a JS file
Example:
Txt file example (values):
Hi = "HELLO WORLD",
Hey = /someregex/g,
Hh = 'haha';
Script example:
window[Hi] = true;
"someregex hi".replace(Hey, "")
window[Hh] = 1;
Here's my script:
var fs = require("fs")
var script = fs.readFileSync("./script.js", "utf8");
var vars = fs.readFileSync("./vars.txt", "utf8");
var replace = {}
var spl = vars.replace(/\r\n/g, "").replace(/ /g, "").split(",");
console.log("caching variables")
for(var dt of spl) {
var splt = dt.split(" = ");
var name = splt[0];
var val = splt[1];
if(!name || !val) {
continue;
}
if(val.endsWith(";")) {
val = val.slice(0, -1);
}
replace[name] = val;
}
console.log("Variables are in cache!")
console.log("Replacing variables in script")
var i = 1;
var t = Object.keys(replace).length;
for(var var_name in replace) {
var var_val = replace[var_name];
var regex = new RegExp(var_name, "g");
console.log(i, "/", t, "Replacing", var_name, "with", var_val, "regex", regex)
script = script.replace(regex, var_val);
i++;
}
console.log("DONE!")
fs.writeFileSync("./dec.js", script, "utf8")
However, when i ~= 100, I have this error:
RangeError: Invalid string length
at RegExp.[Symbol.replace] (native)
at String.replace (native)
EDIT: also, I can see that node.js process is using ~400MB of RAM and I have the error when it reaches 900MB
What's wrong?

Regex exact text match is not working

I am trying to perform exact match of the text keyed in a textbox but, somehow it is working as partial match. I tried different options but could not figure out the cause.
RegExp.escape = function (text) {
//escape the +,[,?... characters
return text.replace(/[-[\]{}()*+?.,\\^$|#\s]/g, "\\$&");
}
var resultLbl = $('#ResultLbl');
$('#SearchTxtBox').bind('change keyup', function () {
resultLbl.text('');
var options = [];
options.push('[1]My]');
options.push('[2]My Name]');
options.push('[3]Name]');
options.push('[2]My Name]');
var searchStr = RegExp.escape($.trim($(this).val()));
var searchArr = [];
if (searchStr != '' && searchStr != null) {
searchStr = searchStr.replace(/\,/g, '\\ ')
searchArr = searchStr.split('\\ ');
}
var search = searchArr[0];
search = search.replace(/[.?*+^$[\]\\(){}|-]/g, '');
var regex = new RegExp($.trim(search), 'gi');
$.each(options, function (i, option) {
if (option.match(regex) !== null) {
resultLbl.append(option + ' ');
}
});
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
Search:
<input type="text" id="SearchTxtBox"/>
<br/>
<label id='ResultLbl'></label>
Expectation:
If you key in the text 'Name' in textbox, only '[3]Name' should be
matched.
If you key in the text 'My Name' in textbox, only '[2]My
Name' should be matched.
Any suggestions are appreciated.

Instead of complex pre-processing, you can just test if the string matches this pattern:
^\[\d+\]<searchStr>\]$
with
var regex = new RegExp("^\\[\\d+\\]" + $.trim(searchStr) + "\\]$", 'gi');
Here is an updated snippet:
RegExp.escape = function (text) {
//escape the +,[,?... characters
return text.replace(/[-[\]{}()*+?.,\\^$|#\s]/g, "\\$&");
}
var resultLbl = $('#ResultLbl');
$('#SearchTxtBox').bind('change keyup', function () {
resultLbl.text('');
var options = [];
options.push('[1]My]');
options.push('[2]My Name]');
options.push('[3]Name]');
options.push('[2]My Name]');
var searchStr = RegExp.escape($.trim($(this).val()));
var regex = new RegExp("^\\[\\d+\\]" + $.trim(searchStr) + "\\]$", 'gi');
$.each(options, function (i, option) {
if (option.match(regex) !== null) {
resultLbl.append(option + ' ');
}
});
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
Search:
<input type="text" id="SearchTxtBox"/>
<br/>
<label id='ResultLbl'></label>

javascript, exception for string/object manipulation

So, I have to functions to turn a string to an object and an object to a string, however I need to account for an except and I am not sure how. Let me show you what I have
parseObjectToUrl: function (obj){
var myStr = "";
var first_iteration = true;
for (var p in obj) {
if(first_iteration){
myStr += p + "=";
first_iteration = false;
}else{
myStr += "&" + p + "=";
}
tObj = obj[p];
var first_inner = true;
for(t in tObj){
if(first_inner){
myStr += t;
first_inner = false;
}else{
myStr += "," + t;
}
yObj = tObj[t];
for( y in yObj){
myStr += "/" + yObj[y];
}
}
}
return myStr;
},
parseObjectFromUrl : function(url){
var builtObj = {};
//remove first slash
url = url.slice(0, 0) + url.slice(1);
var ch = url.split('&');
var tempParent = {};
for (var p in ch) {
var tempSub = {};
var arr = ch[p].split('=');
var keyParent = arr[0];
var splitInside = arr[1].split(",");
for (var i in splitInside) {
var sub = splitInside[i].split('/');
var subKey = sub[0];
tempSub[subKey] = sub.slice(1);
}
tempParent[keyParent] = tempSub;
}
return tempParent
}
So these the string looks like
/module1=mod1/2/3/4,mod2/2/3/4&module2=mod2/3/4/5
and the object looks like
myObj =
{
module1 : { mod1 : [2,3,4] , mod2 [2,3,4]} ,
module2 : { mod2 : [3,4,5]}
}
So these functions work fine for me however I (unfortunately) need to be able to handle the case when the user adds an "/" into the options like -
myObj =
{
module1 : { mod1 : [2/,3/,4/] , mod2 [2,3,4]} ,
module2 : { mod2 : [3,4,5]}
}
I'm sure it's going to throw a wrench in my function because i'm splitting by the "/", so I'm not sure how to get around this. Would i escape the slash? How would that fit into the functions if so? Looking for any advice on this issue. Thanks!
Edit:
I was able to encode the escaped url like :
obj.replace(/([/-])/g, "%2F");
to an escaped url, hoever I am having trouble doing the reverse of this. here is my attempt.
obj.replace(/(%2F)/g, "/");

in my opinion it would be better to use url arrays, but keep in mind the characters for your url could be limited:
maximum length of HTTP GET request?
having said that one could do something like this:
module1[]=1&module1[]=2&module2[]=4&module2[]=3
this is equal to the following pseudo code:
$_GET["module1"] = array(1,2);
$_GET["module2"] = array(4,3);
and use encodeURIComponent & decodeURIComponent for your values
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/encodeURIComponent

javascript: how to modify the query string?

Like
?a=1&b=2&c=3
I only want to change b=6 while keep the other things the same, how to do it?

Following function if you have to replace any b=XXX with b=newBValue
function ReplaceB(strQuery,newBValue)
{
var idxStart= strQuery.indexOf("b=")
if(idxStart<0)
return; // b= not found, nothing to change
var idxFin=strQuery.substr(0,idxStart).indexOf("&");
var newQuery;
if(idxFin<0)
newQuery = strQuery.substr(0,idxStart) + "b="+newBValue
else
newQuery = strQuery.substr(0,idxStart) + "b="+newBValue+strQuery.substr(idxStart+idxFin)
return newQuery;
}

here a small function to do this:
jQuery.replaceURLParam = function (oldURL, replaceParam, newVal) {
var iStart = oldURL .indexOf(replaceParam + '=');
var iEnd = oldURL .substring(iStart + 1).indexOf('&');
var sEnd = oldURL .substring(iStart + iEnd + 1);
var sStart = oldURL .substring(0, iStart);
var newURl = sStart + replaceParam + '=' + newVal;
if (iEnd > 0) {
newURl += sEnd;
}
return newURl;
}
document.body.innerHTML = jQuery.replaceURLParam('www.foo.com?a=1&b=2&c=3', 'b', 6) ;
demo: http://jsfiddle.net/3rkrn/

var queryStr = "?a=1&b=2&c=3";
var startTag = "b=";
var endTag = "&";
var index1 = queryStr.indexOf(startTag) + startTag.length;
var index2 = queryStr.indexOf(endTag,index1);
var newValue = 23;
queryStr = queryStr.substr(0, index1) + newValue + queryStr.substr(index2);
alert(queryStr);
See it here : http://jsfiddle.net/aQL8p/

var test = "?a=1&b=2&c=3".replace(/b=2/gi,"b=6");
alert(test);
Example
var test = "?a=1&b=2&c=3".replace("b=2","b=6");
alert(test);
Example
var test = "?a=1&b=2&c=3".split("b=2").join("b=6");
alert(test);
Example
Regardless of Number
Want to change to value of b regardless of number it is already? Use:
var test = "?a=1&b=2&c=3".replace(/b=\d/gi, "b=6");
alert(test);
Example

var queryString = '?a=1&b=2&c=3'.replace(/([?&;])b=2([$&;])/g, '$1b=6$2');
jsFiddle.
(JavaScript regex does not support lookbehinds).

See if this works for you - a more or less universal urlFor:
https://gist.github.com/4108452
You would simply do
newUrl = urlFor(oldUrl, {b:6});