Develop Reference

Remove and replace consecutive characters

I have that content:
ALL EVERYTHING
I want to remove all and get that string: ALL EVERYTHING.
If I use that code:
var str = $("#post_wall_textarea_parent .emojionearea-editor").html(); // I can't use $("#post_wall_textarea_parent .emojionearea-editor").text(); for many reasons
str_ = str.replace(/ /g, " ");
It gives me that: ALL EVERYTHING.
I want to remove more thant one space between two words.
How could I do to get: ALL EVERYTHING instead of ALL EVERYTHING. ?
Thanks.

Use str.replace(/( )+/g, " ");
const str = "ALL EVERYTHING";
const result = str.replace(/( )+/g, " ");
console.log(result);
`Edited as Dimitri's Comment.

Remove multiple white space between text

var s = "Hello! I'm billy! what's up?";
var result = s.split(" ").join();
console.log(result);
Got this result
Hello!,I'm,,billy!,what's,,,,up?
How can i get rid of this annoying extra spaces between string? So it might look like this.
Hello!,I'm,billy!,what's,up?

Use a regular expression to find all the spaces throughout the string and rejoin with a single space:
var s = "Hello! I'm billy! what's up?";
var result = s.split(/\s+/).join(" ");
console.log(result);
You can also do this without using .split() to return a new array and just use the String.replace() method. The regular expression changes just a little in that case:
var s = "Hello! I'm billy! what's up?";
var result = s.replace(/ +/g, " ");
console.log(result);

You want replace and \s+
\s+ Matches multiple white space character, including space, tab,
form feed, line feed.
trim to remove extra white space at the start and end of the string
var s = " Hello! I'm billy! what's up? ";
console.log(s.replace(/\s+/g, " ").trim());

var s = "Hello! I'm billy! what's up?";
var result = s.replace(/\s+/g,' ').trim();
console.log(result);

The replace() method returns a new string with some or all matches of a pattern replaced by a replacement. The pattern can be a string or a RegExp, and the replacement can be a string or a function to be called for each match.
var str = "Hello! I'm billy! what's up?";
str = str.replace(/ +/g, " ");
console.log(str);
var strr = "Hello! I'm billy! what's up?";
strr = strr.replace(/ +/g, " ");
console.log(strr);

How to execute a capturing group multiple times?

I have this string:
var str = "some text start:anything can be here some other text";
And here is expected result:
//=> some text start:anythingcanbehere some other text
In other word, I'm trying to remove all white spaces between a specific range of such a string.
Also Here is what I have tried:
(start:)(?:(\S+)(\s+))(.*)(?= some)
It works as well, but I should execute it several times to achieve expected result .. How can I use \1+ in my regex to run it several times?

You can't do what you want with a simple regexp replace, because a capture group can only capture one string -- there's no looping. Javascript allows you to provide a function as the replacement, and it can perform more complex operations on the captured strings.
var str = "some text start:anything can be here some other text";
var newstr = str.replace(/(start:)(.*)(?= some)/, function(match, g1, g2) {
return g1 + g2.replace(/ /g, '');
});
alert(newstr);

Using replace with a callback:
var repl = str.replace(/(start:.*?)(?= some\b)/, function(_, $1) {
return $1.replace(/\s+/g, ''); });
//=> some text start:anythingcanbehere some other text

How to remove the extra spaces in a string?

What function will turn this contains spaces into this contains spaces using javascript?
I've tried the following, using similar SO questions, but could not get this to work.
var string = " this contains spaces ";
newString = string.replace(/\s+/g,''); // "thiscontainsspaces"
newString = string.replace(/ +/g,''); //"thiscontainsspaces"
Is there a simple pure javascript way to accomplish this?

You're close.
Remember that replace replaces the found text with the second argument. So:
newString = string.replace(/\s+/g,''); // "thiscontainsspaces"
Finds any number of sequential spaces and removes them. Try replacing them with a single space instead!
newString = string.replace(/\s+/g,' ').trim();

string.replace(/\s+/g, ' ').trim()

Try this one, this will replace 2 or 2+ white spaces from string.
const string = " this contains spaces ";
string.replace(/\s{2,}/g, ' ').trim()
Output
this contains spaces

I figured out one way, but am curious if there is a better way...
string.replace(/\s+/g,' ').trim()

I got the same problem and I fixed like this
Text = Text.replace(/ {1,}/g," ");
Text = Text.trim();

I think images always explain it's good, basically what you see that the regex \s meaning in regex is whitespace. the + says it's can be multiply times. /g symbol that it's looks globally (replace by default looks for the first occur without the /g added). and the trim will remove the last and first whitespaces if exists.
Finally, To remove extra whitespaces you will need this code:
newString = string.replace(/\s+/g,' ').trim();

We can use the below approach to remove extra space in a sentence/word.
sentence.split(' ').filter(word => word).join(' ')

Raw Javascript Solution:
var str = ' k g alok deshwal';
function removeMoreThanOneSpace() {
String.prototype.removeSpaceByLength=function(index, length) {
console.log("in remove", this.substr(0, index));
return this.substr(0, index) + this.substr(length);
}
for(let i = 0; i < str.length-1; i++) {
if(str[i] === " " && str[i+1] === " ") {
str = str.removeSpaceByLength(i, i+1);
i = i-1;
}
}
return str;
}
console.log(removeMoreThanOneSpace(str));

var s=" i am a student "
var r='';
console.log(s);
var i,j;
j=0;
for(k=0; s[k]!=undefined; k++);// to calculate the length of a string
for(i=0;i<k;i++){
if(s[i]!==' '){
for(;s[i]!==' ';i++){
r+=s[i];
}
r+=' ';
}
}
console.log(r);

// Here my solution
const trimString = value => {
const allStringElementsToArray = value.split('');
// transform "abcd efgh" to ['a', 'b', 'c', 'd',' ','e', 'f','g','h']
const allElementsSanitized = allStringElementsToArray.map(e => e.trim());
// Remove all blank spaces from array
const finalValue = allElementsSanitized.join('');
// Transform the sanitized array ['a','b','c','d','e','f','g','h'] to 'abcdefgh'
return finalValue;
}

I have tried regex to solve this problem :
let temp=text.replace(/\s{2,}/g, ' ').trim()
console.log(temp);
input="Plese complete your work on Time"
output="Please complete your work on Time"

//This code remove extra spaces with out using "string objectives"
s=" This Is Working On Functions "
console.log(s)
final="";
res='';
function result(s) {
for(var i=0;i<s.length;i++)
{
if(!(final==""&&s[i]==" ")&&!(s[i]===" "&& s[i+1] ===" ")){
final+=s[i];
}
}
console.log(final);
}
result(s);

How can I perform a str_replace in JavaScript, replacing text in JavaScript?

I want to use str_replace or its similar alternative to replace some text in JavaScript.
var text = "this is some sample text that i want to replace";
var new_text = replace_in_javascript("want", "dont want", text);
document.write(new_text);
should give
this is some sample text that i dont want to replace
If you are going to regex, what are the performance implications in
comparison to the built in replacement methods.

You would use the replace method:
text = text.replace('old', 'new');
The first argument is what you're looking for, obviously. It can also accept regular expressions.
Just remember that it does not change the original string. It only returns the new value.

More simply:
city_name=city_name.replace(/ /gi,'_');
Replaces all spaces with '_'!

All these methods don't modify original value, returns new strings.
var city_name = 'Some text with spaces';
Replaces 1st space with _
city_name.replace(' ', '_'); // Returns: "Some_text with spaces" (replaced only 1st match)
Replaces all spaces with _ using regex. If you need to use regex, then i recommend testing it with https://regex101.com/
city_name.replace(/ /gi,'_'); // Returns: Some_text_with_spaces
Replaces all spaces with _ without regex. Functional way.
city_name.split(' ').join('_'); // Returns: Some_text_with_spaces

You should write something like that :
var text = "this is some sample text that i want to replace";
var new_text = text.replace("want", "dont want");
document.write(new_text);

The code that others are giving you only replace one occurrence, while using regular expressions replaces them all (like #sorgit said). To replace all the "want" with "not want", us this code:
var text = "this is some sample text that i want to replace";
var new_text = text.replace(/want/g, "dont want");
document.write(new_text);
The variable "new_text" will result in being "this is some sample text that i dont want to replace".
To get a quick guide to regular expressions, go here:
http://www.cheatography.com/davechild/cheat-sheets/regular-expressions/
To learn more about str.replace(), go here:
https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Global_Objects/String/replace
Good luck!

that function replaces only one occurrence.. if you need to replace
multiple occurrences you should try this function:
http://phpjs.org/functions/str_replace:527
Not necessarily.
see the Hans Kesting answer:
city_name = city_name.replace(/ /gi,'_');

Using regex for string replacement is significantly slower than using a string replace.
As demonstrated on JSPerf, you can have different levels of efficiency for creating a regex, but all of them are significantly slower than a simple string replace. The regex is slower because:
Fixed-string matches don't have backtracking, compilation steps, ranges, character classes, or a host of other features that slow down the regular expression engine. There are certainly ways to optimize regex matches, but I think it's unlikely to beat indexing into a string in the common case.
For a simple test run on the JS perf page, I've documented some of the results:
<script>
// Setup
var startString = "xxxxxxxxxabcxxxxxxabcxx";
var endStringRegEx = undefined;
var endStringString = undefined;
var endStringRegExNewStr = undefined;
var endStringRegExNew = undefined;
var endStringStoredRegEx = undefined;
var re = new RegExp("abc", "g");
</script>
<script>
// Tests
endStringRegEx = startString.replace(/abc/g, "def") // Regex
endStringString = startString.replace("abc", "def", "g") // String
endStringRegExNewStr = startString.replace(new RegExp("abc", "g"), "def"); // New Regex String
endStringRegExNew = startString.replace(new RegExp(/abc/g), "def"); // New Regexp
endStringStoredRegEx = startString.replace(re, "def") // saved regex
</script>
The results for Chrome 68 are as follows:
String replace: 9,936,093 operations/sec
Saved regex: 5,725,506 operations/sec
Regex: 5,529,504 operations/sec
New Regex String: 3,571,180 operations/sec
New Regex: 3,224,919 operations/sec
From the sake of completeness of this answer (borrowing from the comments), it's worth mentioning that .replace only replaces the first instance of the matched character. Its only possible to replace all instances with //g. The performance trade off and code elegance could be argued to be worse if replacing multiple instances name.replace(' ', '_').replace(' ', '_').replace(' ', '_'); or worse while (name.includes(' ')) { name = name.replace(' ', '_') }

var new_text = text.replace("want", "dont want");

hm.. Did you check replace() ?
Your code will look like this
var text = "this is some sample text that i want to replace";
var new_text = text.replace("want", "dont want");
document.write(new_text);

JavaScript has replace() method of String object for replacing substrings. This method can have two arguments. The first argument can be a string or a regular expression pattern (regExp object) and the second argument can be a string or a function. An example of replace() method having both string arguments is shown below.
var text = 'one, two, three, one, five, one';
var new_text = text.replace('one', 'ten');
console.log(new_text) //ten, two, three, one, five, one
Note that if the first argument is the string, only the first occurrence of the substring is replaced as in the example above. To replace all occurrences of the substring you need to provide a regular expression with a g (global) flag. If you do not provide the global flag, only the first occurrence of the substring will be replaced even if you provide the regular expression as the first argument. So let's replace all occurrences of one in the above example.
var text = 'one, two, three, one, five, one';
var new_text = text.replace(/one/g, 'ten');
console.log(new_text) //ten, two, three, ten, five, ten
Note that you do not wrap the regular expression pattern in quotes which will make it a string not a regExp object. To do a case insensitive replacement you need to provide additional flag i which makes the pattern case-insensitive. In that case the above regular expression will be /one/gi. Notice the i flag added here.
If the second argument has a function and if there is a match the function is passed with three arguments. The arguments the function gets are the match, position of the match and the original text. You need to return what that match should be replaced with. For example,
var text = 'one, two, three, one, five, one';
var new_text = text.replace(/one/g, function(match, pos, text){
return 'ten';
});
console.log(new_text) //ten, two, three, ten, five, ten
You can have more control over the replacement text using a function as the second argument.

In JavaScript, you call the replace method on the String object, e.g. "this is some sample text that i want to replace".replace("want", "dont want"), which will return the replaced string.
var text = "this is some sample text that i want to replace";
var new_text = text.replace("want", "dont want"); // new_text now stores the replaced string, leaving the original untouched

You can use
text.replace('old', 'new')
And to change multiple values in one string at once, for example to change # to string v and _ to string w:
text.replace(/#|_/g,function(match) {return (match=="#")? v: w;});

There are already multiple answers using str.replace() (which is fair enough for this question) and regex but you can use combination of str.split() and join() together which is faster than str.replace() and regex.
Below is working example:
var text = "this is some sample text that i want to replace";
console.log(text.split("want").join("dont want"));

If you really want a equivalent to PHP's str_replace you can use Locutus. PHP's version of str_replace support more option then what the JavaScript String.prototype.replace supports.
For example tags:
//PHP
$bodytag = str_replace("%body%", "black", "<body text='%body%'>");
//JS with Locutus
var $bodytag = str_replace(['{body}', 'black', '<body text='{body}'>')
or array's
//PHP
$vowels = array("a", "e", "i", "o", "u", "A", "E", "I", "O", "U");
$onlyconsonants = str_replace($vowels, "", "Hello World of PHP");
//JS with Locutus
var $vowels = ["a", "e", "i", "o", "u", "A", "E", "I", "O", "U"];
var $onlyconsonants = str_replace($vowels, "", "Hello World of PHP");
Also this doesn't use regex instead it uses for loops. If you not want to use regex but want simple string replace you can use something like this ( based on Locutus )
function str_replace (search, replace, subject) {
var i = 0
var j = 0
var temp = ''
var repl = ''
var sl = 0
var fl = 0
var f = [].concat(search)
var r = [].concat(replace)
var s = subject
s = [].concat(s)
for (i = 0, sl = s.length; i < sl; i++) {
if (s[i] === '') {
continue
}
for (j = 0, fl = f.length; j < fl; j++) {
temp = s[i] + ''
repl = r[0]
s[i] = (temp).split(f[j]).join(repl)
if (typeof countObj !== 'undefined') {
countObj.value += ((temp.split(f[j])).length - 1)
}
}
}
return s[0]
}
var text = "this is some sample text that i want to replace";
var new_text = str_replace ("want", "dont want", text)
document.write(new_text)
for more info see the source code https://github.com/kvz/locutus/blob/master/src/php/strings/str_replace.js

You have the following options:
Replace the first occurrence
var text = "this is some sample text that i want to replace and this i WANT to replace as well.";
var new_text = text.replace('want', 'dont want');
// new_text is "this is some sample text that i dont want to replace and this i WANT to replace as well"
console.log(new_text)
Replace all occurrences - case sensitive
var text = "this is some sample text that i want to replace and this i WANT to replace as well.";
var new_text = text.replace(/want/g, 'dont want');
// new_text is "this is some sample text that i dont want to replace and this i WANT to replace as well
console.log(new_text)
Replace all occurrences - case insensitive
var text = "this is some sample text that i want to replace and this i WANT to replace as well.";
var new_text = text.replace(/want/gi, 'dont want');
// new_text is "this is some sample text that i dont want to replace and this i dont want to replace as well
console.log(new_text)
More info -> here

In Javascript, replace function available to replace sub-string from given string with new one.
Use:
var text = "this is some sample text that i want to replace";
var new_text = text.replace("want", "dont want");
console.log(new_text);
You can even use regular expression with this function. For example, if want to replace all occurrences of , with ..
var text = "123,123,123";
var new_text = text.replace(/,/g, ".");
console.log(new_text);
Here g modifier used to match globally all available matches.

Method to replace substring in a sentence using React:
const replace_in_javascript = (oldSubStr, newSubStr, sentence) => {
let newStr = "";
let i = 0;
sentence.split(" ").forEach(obj => {
if (obj.toUpperCase() === oldSubStr.toUpperCase()) {
newStr = i === 0 ? newSubStr : newStr + " " + newSubStr;
i = i + 1;
} else {
newStr = i === 0 ? obj : newStr + " " + obj;
i = i + 1;
}
});
return newStr;
};
RunMethodHere

If you don't want to use regex then you can use this function which will replace all in a string
Source Code:
function ReplaceAll(mystring, search_word, replace_with)
{
while (mystring.includes(search_word))
{
mystring = mystring.replace(search_word, replace_with);
}
return mystring;
}
How to use:
var mystring = ReplaceAll("Test Test", "Test", "Hello");

Use JS String.prototype.replace first argument should be Regex pattern or String and Second argument should be a String or function.
str.replace(regexp|substr, newSubStr|function);
Ex:
var str = 'this is some sample text that i want to replace';
var newstr = str.replace(/want/i, "dont't want");
document.write(newstr); // this is some sample text that i don't want to replace

ES2021 / ES12
String.prototype.replaceAll()
is trying to bring the full replacement option even when the input pattern is a string.
const str = "Backbencher sits at the Back";
const newStr = str.replaceAll("Back", "Front");
console.log(newStr); // "Frontbencher sits at the Front"
1- String.prototype.replace()
We can do a full **replacement** only if we supply the pattern as a regular expression.
const str = "Backbencher sits at the Back";
const newStr = str.replace(/Back/g, "Front");
console.log(newStr); // "Frontbencher sits at the Front"
If the input pattern is a string, replace() method only replaces the first occurrence.
const str = "Backbencher sits at the Back";
const newStr = str.replace("Back", "Front");
console.log(newStr); // "Frontbencher sits at the Back"
2- You can use split and join
const str = "Backbencher sits at the Back";
const newStr = str.split("Back").join("Front");
console.log(newStr); // "Frontbencher sits at the Front"

function str_replace($old, $new, $text)
{
return ($text+"").split($old).join($new);
}
You do not need additional libraries.

In ECMAScript 2021, you can use replaceAll can be used.
const str = "string1 string1 string1"
const newStr = str.replaceAll("string1", "string2");
console.log(newStr)
// "string2 string2 string2"

simplest form as below
if you need to replace only first occurrence
var newString = oldStr.replace('want', 'dont want');
if you want ot repalce all occurenace
var newString = oldStr.replace(want/g, 'dont want');

Added a method replace_in_javascript which will satisfy your requirement. Also found that you are writing a string "new_text" in document.write() which is supposed to refer to a variable new_text.
let replace_in_javascript= (replaceble, replaceTo, text) => {
return text.replace(replaceble, replaceTo)
}
var text = "this is some sample text that i want to replace";
var new_text = replace_in_javascript("want", "dont want", text);
document.write(new_text);