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Given a string:
string = "Test abc test test abc test test test abc test test abc";
This seems to only remove the first occurrence of abc
in the string above:
string = string.replace('abc', '');
How do I replace all occurrences of it?
Given a string:
string = "Test abc test test abc test test test abc test test abc";
This seems to only remove the first occurrence of abc
in the string above:
string = string.replace('abc', '');
How do I replace all occurrences of it?
Share Improve this question edited Mar 19, 2024 at 16:06 mikemaccana 123k110 gold badges425 silver badges529 bronze badges asked Jul 17, 2009 at 17:53 AliAli 267k267 gold badges590 silver badges784 bronze badges 2 |50 Answers
Reset to default 1 2 Next 5246As of August 2020: Modern browsers have support for the String.replaceAll()
method defined by the ECMAScript 2021 language specification.
For older/legacy browsers:
function escapeRegExp(str) {
return str.replace(/[.*+?^${}()|[\]\\]/g, '\\$&'); // $& means the whole matched string
}
function replaceAll(str, find, replace) {
return str.replace(new RegExp(escapeRegExp(find), 'g'), replace);
}
Here is how this answer evolved:
str = str.replace(/abc/g, '');
In response to comment "what's if 'abc' is passed as a variable?":
var find = 'abc';
var re = new RegExp(find, 'g');
str = str.replace(re, '');
In response to Click Upvote's comment, you could simplify it even more:
function replaceAll(str, find, replace) {
return str.replace(new RegExp(find, 'g'), replace);
}
Note: Regular expressions contain special (meta) characters, and as such it is dangerous to blindly pass an argument in the find
function above without pre-processing it to escape those characters. This is covered in the Mozilla Developer Network's JavaScript Guide on Regular Expressions, where they present the following utility function (which has changed at least twice since this answer was originally written, so make sure to check the MDN site for potential updates):
function escapeRegExp(string) {
return string.replace(/[.*+?^${}()|[\]\\]/g, '\\$&'); // $& means the whole matched string
}
So in order to make the replaceAll()
function above safer, it could be modified to the following if you also include escapeRegExp
:
function replaceAll(str, find, replace) {
return str.replace(new RegExp(escapeRegExp(find), 'g'), replace);
}
For the sake of completeness, I got to thinking about which method I should use to do this. There are basically two ways to do this as suggested by the other answers on this page.
Note: In general, extending the built-in prototypes in JavaScript is generally not recommended. I am providing as extensions on the String prototype simply for purposes of illustration, showing different implementations of a hypothetical standard method on the String
built-in prototype.
Regular Expression Based Implementation
String.prototype.replaceAll = function(search, replacement) {
var target = this;
return target.replace(new RegExp(search, 'g'), replacement);
};
Split and Join (Functional) Implementation
String.prototype.replaceAll = function(search, replacement) {
var target = this;
return target.split(search).join(replacement);
};
Not knowing too much about how regular expressions work behind the scenes in terms of efficiency, I tended to lean toward the split and join implementation in the past without thinking about performance. When I did wonder which was more efficient, and by what margin, I used it as an excuse to find out.
On my Chrome Windows 8 machine, the regular expression based implementation is the fastest, with the split and join implementation being 53% slower. Meaning the regular expressions are twice as fast for the lorem ipsum input I used.
Check out this benchmark running these two implementations against each other.
As noted in the comment below by @ThomasLeduc and others, there could be an issue with the regular expression-based implementation if search
contains certain characters which are reserved as special characters in regular expressions. The implementation assumes that the caller will escape the string beforehand or will only pass strings that are without the characters in the table in Regular Expressions (MDN).
MDN also provides an implementation to escape our strings. It would be nice if this was also standardized as RegExp.escape(str)
, but alas, it does not exist:
function escapeRegExp(str) {
return str.replace(/[.*+?^${}()|[\]\\]/g, "\\$&"); // $& means the whole matched string
}
We could call escapeRegExp
within our String.prototype.replaceAll
implementation, however, I'm not sure how much this will affect the performance (potentially even for strings for which the escape is not needed, like all alphanumeric strings).
In the latest versions of most popular browsers, you can use replaceAll
as shown here:
let result = "1 abc 2 abc 3".replaceAll("abc", "xyz");
// `result` is "1 xyz 2 xyz 3"
But check Can I use or another compatibility table first to make sure the browsers you're targeting have added support for it first.
For Node.js and compatibility with older/non-current browsers:
Note: Don't use the following solution in performance critical code.
As an alternative to regular expressions for a simple literal string, you could use
str = "Test abc test test abc test...".split("abc").join("");
The general pattern is
str.split(search).join(replacement)
This used to be faster in some cases than using replaceAll
and a regular expression, but that doesn't seem to be the case anymore in modern browsers.
Benchmark: https://jsben.ch/TZYzj
Conclusion:
If you have a performance-critical use case (e.g., processing hundreds of strings), use the regular expression method. But for most typical use cases, this is well worth not having to worry about special characters.
These are the most common and readable methods.
var str = "Test abc test test abc test test test abc test test abc"
Method 1:
str = str.replace(/abc/g, "replaced text");
Method 2:
str = str.split("abc").join("replaced text");
Method 3:
str = str.replace(new RegExp("abc", "g"), "replaced text");
Method 4:
while(str.includes("abc")){
str = str.replace("abc", "replaced text");
}
Output:
console.log(str);
// Test replaced text test test replaced text test test test replaced text test test replaced text
Use word boundaries (\b
)
'a cat is not a caterpillar'.replace(/\bcat\b/gi,'dog');
//"a dog is not a caterpillar"
This is a simple regex that avoids replacing parts of words in most cases. However, a dash -
is still considered a word boundary. So conditionals can be used in this case to avoid replacing strings like cool-cat
:
'a cat is not a cool-cat'.replace(/\bcat\b/gi,'dog');//wrong
//"a dog is not a cool-dog" -- nips
'a cat is not a cool-cat'.replace(/(?:\b([^-]))cat(?:\b([^-]))/gi,'$1dog$2');
//"a dog is not a cool-cat"
Basically, this question is the same as the question here: Replace " ' " with " '' " in JavaScript
Regexp isn't the only way to replace multiple occurrences of a substring, far from it. Think flexible, think split!
var newText = "the cat looks like a cat".split('cat').join('dog');
Alternatively, to prevent replacing word parts—which the approved answer will do, too! You can get around this issue using regular expressions that are, I admit, somewhat more complex and as an upshot of that, a tad slower, too:
var regText = "the cat looks like a cat".replace(/(?:(^|[^a-z]))(([^a-z]*)(?=cat)cat)(?![a-z])/gi,"$1dog");
The output is the same as the accepted answer, however, using the /cat/g
expression on this string:
var oops = 'the cat looks like a cat, not a caterpillar or coolcat'.replace(/cat/g,'dog');
//returns "the dog looks like a dog, not a dogerpillar or cooldog" ??
Oops indeed, this probably isn't what you want. What is, then? IMHO, a regex that only replaces 'cat' conditionally (i.e., not part of a word), like so:
var caterpillar = 'the cat looks like a cat, not a caterpillar or coolcat'.replace(/(?:(^|[^a-z]))(([^a-z]*)(?=cat)cat)(?![a-z])/gi,"$1dog");
//return "the dog looks like a dog, not a caterpillar or coolcat"
My guess is, this meets your needs. It's not foolproof, of course, but it should be enough to get you started. I'd recommend reading some more on these pages. This'll prove useful in perfecting this expression to meet your specific needs.
RegExp (regular expression) object
Regular-Expressions.info
Here is an example of .replace
used with a callback function. In this case, it dramatically simplifies the expression and provides even more flexibility, like replacing with correct capitalisation or replacing both cat
and cats
in one go:
'Two cats are not 1 Cat! They\'re just cool-cats, you caterpillar'
.replace(/(^|.\b)(cat)(s?\b.|$)/gi,function(all,char1,cat,char2)
{
// Check 1st, capitalize if required
var replacement = (cat.charAt(0) === 'C' ? 'D' : 'd') + 'og';
if (char1 === ' ' && char2 === 's')
{ // Replace plurals, too
cat = replacement + 's';
}
else
{ // Do not replace if dashes are matched
cat = char1 === '-' || char2 === '-' ? cat : replacement;
}
return char1 + cat + char2;//return replacement string
});
//returns:
//Two dogs are not 1 Dog! They're just cool-cats, you caterpillar
Match against a global regular expression:
anotherString = someString.replace(/cat/g, 'dog');
str = str.replace(/abc/g, '');
Or try the replaceAll
method, as recommended in this answer:
str = str.replaceAll('abc', '');
or:
var search = 'abc';
str = str.replaceAll(search, '');
EDIT: Clarification about replaceAll
availability
The replaceAll
method is added to String
's prototype. This means it will be available for all string objects/literals.
Example:
var output = "test this".replaceAll('this', 'that'); // output is 'test that'.
output = output.replaceAll('that', 'this'); // output is 'test this'
Use a regular expression:
str.replace(/abc/g, '');
Performance
Today 27.12.2019 I perform tests on macOS v10.13.6 (High Sierra) for the chosen solutions.
Conclusions
- The
str.replace(/abc/g, '');
(C) is a good cross-browser fast solution for all strings. - Solutions based on
split-join
(A,B) orreplace
(C,D) are fast - Solutions based on
while
(E,F,G,H) are slow - usually ~4 times slower for small strings and about ~3000 times (!) slower for long strings - The recurrence solutions (RA,RB) are slow and do not work for long strings
I also create my own solution. It looks like currently it is the shortest one which does the question job:
str.split`abc`.join``
str = "Test abc test test abc test test test abc test test abc";
str = str.split`abc`.join``
console.log(str);
Details
The tests were performed on Chrome 79.0, Safari 13.0.4 and Firefox 71.0 (64 bit). The tests RA
and RB
use recursion. Results
Short string - 55 characters
You can run tests on your machine HERE. Results for Chrome:
Long string: 275 000 characters
The recursive solutions RA and RB gives
RangeError: Maximum call stack size exceeded
For 1M characters they even break Chrome
I try to perform tests for 1M characters for other solutions, but E,F,G,H takes so much time that browser ask me to break script so I shrink test string to 275K characters. You can run tests on your machine HERE. Results for Chrome
Code used in tests
var t="Test abc test test abc test test test abc test test abc"; // .repeat(5000)
var log = (version,result) => console.log(`${version}: ${result}`);
function A(str) {
return str.split('abc').join('');
}
function B(str) {
return str.split`abc`.join``; // my proposition
}
function C(str) {
return str.replace(/abc/g, '');
}
function D(str) {
return str.replace(new RegExp("abc", "g"), '');
}
function E(str) {
while (str.indexOf('abc') !== -1) { str = str.replace('abc', ''); }
return str;
}
function F(str) {
while (str.indexOf('abc') !== -1) { str = str.replace(/abc/, ''); }
return str;
}
function G(str) {
while(str.includes("abc")) { str = str.replace('abc', ''); }
return str;
}
// src: https://stackoverflow.com/a/56989553/860099
function H(str)
{
let i = -1
let find = 'abc';
let newToken = '';
if (!str)
{
if ((str == null) && (find == null)) return newToken;
return str;
}
while ((
i = str.indexOf(
find, i >= 0 ? i + newToken.length : 0
)) !== -1
)
{
str = str.substring(0, i) +
newToken +
str.substring(i + find.length);
}
return str;
}
// src: https://stackoverflow.com/a/22870785/860099
function RA(string, prevstring) {
var omit = 'abc';
var place = '';
if (prevstring && string === prevstring)
return string;
prevstring = string.replace(omit, place);
return RA(prevstring, string)
}
// src: https://stackoverflow.com/a/26107132/860099
function RB(str) {
var find = 'abc';
var replace = '';
var i = str.indexOf(find);
if (i > -1){
str = str.replace(find, replace);
i = i + replace.length;
var st2 = str.substring(i);
if(st2.indexOf(find) > -1){
str = str.substring(0,i) + RB(st2, find, replace);
}
}
return str;
}
log('A ', A(t));
log('B ', B(t));
log('C ', C(t));
log('D ', D(t));
log('E ', E(t));
log('F ', F(t));
log('G ', G(t));
log('H ', H(t));
log('RA', RA(t)); // use reccurence
log('RB', RB(t)); // use reccurence
<p style="color:red">This snippet only presents codes used in tests. It not perform test itself!<p>
Loop it until number occurrences comes to 0, like this:
function replaceAll(find, replace, str) {
while (str.indexOf(find) > -1) {
str = str.replace(find, replace);
}
return str;
}
This is the fastest version that doesn't use regular expressions.
Revised jsperf
replaceAll = function(string, omit, place, prevstring) {
if (prevstring && string === prevstring)
return string;
prevstring = string.replace(omit, place);
return replaceAll(prevstring, omit, place, string)
}
It is almost twice as fast as the split and join method.
As pointed out in a comment here, this will not work if your omit
variable contains place
, as in: replaceAll("string", "s", "ss")
, because it will always be able to replace another occurrence of the word.
There is another jsperf with variants on my recursive replace that go even faster (http://jsperf.com/replace-all-vs-split-join/12)!
- Update July 27th 2017: It looks like RegExp now has the fastest performance in the recently released Chrome 59.
If what you want to find is already in a string, and you don't have a regex escaper handy, you can use join/split:
function replaceMulti(haystack, needle, replacement)
{
return haystack.split(needle).join(replacement);
}
someString = 'the cat looks like a cat';
console.log(replaceMulti(someString, 'cat', 'dog'));
Of course in 2021 the right answer is:
String.prototype.replaceAll()
console.log(
'Change this and this for me'.replaceAll('this','that') // Normal case
);
console.log(
'aaaaaa'.replaceAll('aa','a') // Challenged case
);
If you don't want to deal with replace() + RegExp.
But what if the browser is from before 2020?
In this case we need polyfill (forcing older browsers to support new features) (I think for a few years will be necessary). I could not find a completely right method in answers. So I suggest this function that will be defined as a polyfill.
My suggested options for replaceAll
polyfill:
replaceAll
polyfill (with global-flag error) (more principled version)
if (!String.prototype.replaceAll) { // Check if the native function not exist
Object.defineProperty(String.prototype, 'replaceAll', { // Define replaceAll as a prototype for (Mother/Any) String
configurable: true, writable: true, enumerable: false, // Editable & non-enumerable property (As it should be)
value: function(search, replace) { // Set the function by closest input names (For good info in consoles)
return this.replace( // Using native String.prototype.replace()
Object.prototype.toString.call(search) === '[object RegExp]' // IsRegExp?
? search.global // Is the RegEx global?
? search // So pass it
: function(){throw new TypeError('replaceAll called with a non-global RegExp argument')}() // If not throw an error
: RegExp(String(search).replace(/[.^$*+?()[{|\\]/g, "\\$&"), "g"), // Replace all reserved characters with '\' then make a global 'g' RegExp
replace); // passing second argument
}
});
}
replaceAll
polyfill (With handling global-flag missing by itself) (my first preference) - Why?
if (!String.prototype.replaceAll) { // Check if the native function not exist
Object.defineProperty(String.prototype, 'replaceAll', { // Define replaceAll as a prototype for (Mother/Any) String
configurable: true, writable: true, enumerable: false, // Editable & non-enumerable property (As it should be)
value: function(search, replace) { // Set the function by closest input names (For good info in consoles)
return this.replace( // Using native String.prototype.replace()
Object.prototype.toString.call(search) === '[object RegExp]' // IsRegExp?
? search.global // Is the RegEx global?
? search // So pass it
: RegExp(search.source, /\/([a-z]*)$/.exec(search.toString())[1] + 'g') // If not, make a global clone from the RegEx
: RegExp(String(search).replace(/[.^$*+?()[{|\\]/g, "\\$&"), "g"), // Replace all reserved characters with '\' then make a global 'g' RegExp
replace); // passing second argument
}
});
}
Minified (my first preference):
if(!String.prototype.replaceAll){Object.defineProperty(String.prototype,'replaceAll',{configurable:!0,writable:!0,enumerable:!1,value:function(search,replace){return this.replace(Object.prototype.toString.call(search)==='[object RegExp]'?search.global?search:RegExp(search.source,/\/([a-z]*)$/.exec(search.toString())[1]+'g'):RegExp(String(search).replace(/[.^$*+?()[{|\\]/g,"\\$&"),"g"),replace)}})}
Try it:
if(!String.prototype.replaceAll){Object.defineProperty(String.prototype,'replaceAll',{configurable:!0,writable:!0,enumerable:!1,value:function(search,replace){return this.replace(Object.prototype.toString.call(search)==='[object RegExp]'?search.global?search:RegExp(search.source,/\/([a-z]*)$/.exec(search.toString())[1]+'g'):RegExp(String(search).replace(/[.^$*+?()[{|\\]/g,"\\$&"),"g"),replace)}})}
console.log(
'Change this and this for me'.replaceAll('this','that')
); // Change that and that for me
console.log(
'aaaaaa'.replaceAll('aa','a')
); // aaa
console.log(
'{} (*) (*) (RegEx) (*) (\*) (\\*) [reserved characters]'.replaceAll('(*)','X')
); // {} X X (RegEx) X X (\*) [reserved characters]
console.log(
'How (replace) (XX) with $1?'.replaceAll(/(xx)/gi,'$$1')
); // How (replace) ($1) with $1?
console.log(
'Here is some numbers 1234567890 1000000 123123.'.replaceAll(/\d+/g,'***')
); // Here is some numbers *** *** *** and need to be replaced.
console.log(
'Remove numbers under 233: 236 229 711 200 5'.replaceAll(/\d+/g, function(m) {
return parseFloat(m) < 233 ? '' : m
})
); // Remove numbers under 233: 236 711
console.log(
'null'.replaceAll(null,'x')
); // x
// The difference between My first preference and the original:
// Now in 2022 with browsers > 2020 it should throw an error (But possible it be changed in future)
// console.log(
// 'xyz ABC abc ABC abc xyz'.replaceAll(/abc/i,'')
// );
// Browsers < 2020:
// xyz xyz
// Browsers > 2020
// TypeError: String.prototype.replaceAll called with a non-global RegExp
Browser support:
- Internet Explorer 9 and later (rested on Internet Explorer 11).
- All other browsers (after 2012).
The result is the same as the native replaceAll in case of the first argument input is:
null
, undefined
, Object
, Function
, Date
, ... , RegExp
, Number
, String
, ...
Ref: 22.1.3.19 String.prototype.replaceAll ( searchValue, replaceValue) + RegExp Syntax
Important note: As some professionals mention it, many of recursive functions that suggested in answers, will return the wrong result. (Try them with the challenged case of the above snippet.)
Maybe some tricky methods like .split('searchValue').join('replaceValue')
or some well managed functions give same result, but definitely with much lower performance than native replaceAll()
/ polyfill replaceAll()
/ replace() + RegExp
Other methods of polyfill assignment
Naive, but supports even older browsers (be better to avoid)
For example, we can support IE7+ too, by not using Object.defineProperty() and using my old naive assignment method:
if (!String.prototype.replaceAll) {
String.prototype.replaceAll = function(search, replace) { // <-- Naive method for assignment
// ... (Polyfill code Here)
}
}
And it should work well for basic uses on IE7+.
But as here @sebastian-simon explained about, that can make secondary problems in case of more advanced uses. E.g.:
for (var k in 'hi') console.log(k);
// 0
// 1
// replaceAll <-- ?
Fully trustable, but heavy
In fact, my suggested option is a little optimistic. Like we trusted the environment (browser and Node.js), it is definitely for around 2012-2021. Also it is a standard/famous one, so it does not require any special consideration.
But there can be even older browsers or some unexpected problems, and polyfills still can support and solve more possible environment problems. So in case we need the maximum support that is possible, we can use polyfill libraries like:
https://polyfill.io/
Specially for replaceAll:
<script src="https://polyfill.io/v3/polyfill.min.js?features=String.prototype.replaceAll"></script>
function replaceAll(str, find, replace) {
var i = str.indexOf(find);
if (i > -1){
str = str.replace(find, replace);
i = i + replace.length;
var st2 = str.substring(i);
if(st2.indexOf(find) > -1){
str = str.substring(0,i) + replaceAll(st2, find, replace);
}
}
return str;
}
I like this method (it looks a little cleaner):
text = text.replace(new RegExp("cat","g"), "dog");
while (str.indexOf('abc') !== -1)
{
str = str.replace('abc', '');
}
As of August 2020 there is a Stage 4 proposal to ECMAScript that adds the replaceAll
method to String
.
It's now supported in Chrome 85+, Edge 85+, Firefox 77+, Safari 13.1+.
The usage is the same as the replace
method:
String.prototype.replaceAll(searchValue, replaceValue)
Here's an example usage:
'Test abc test test abc test.'.replaceAll('abc', 'foo'); // -> 'Test foo test test foo test.'
It's supported in most modern browsers, but there exist polyfills:
- core-js
- es-shims
It is supported in the V8 engine behind an experimental flag --harmony-string-replaceall
.
Read more on the V8 website.
If the string contains a similar pattern like abccc
, you can use this:
str.replace(/abc(\s|$)/g, "")
The previous answers are way too complicated. Just use the replace function like this:
str.replace(/your_regex_pattern/g, replacement_string);
Example:
var str = "Test abc test test abc test test test abc test test abc";
var res = str.replace(/[abc]+/g, "");
console.log(res);
After several trials and a lot of fails, I found that the below function seems to be the best all-rounder when it comes to browser compatibility and ease of use. This is the only working solution for older browsers that I found. (Yes, even though old browser are discouraged and outdated, some legacy applications still make heavy use of OLE browsers (such as old Visual Basic 6 applications or Excel .xlsm macros with forms.)
Anyway, here's the simple function.
function replaceAll(str, match, replacement){
return str.split(match).join(replacement);
}
Although people have mentioned the use of regex, there's a better approach if you want to replace the text irrespective of the case of the text. Like uppercase or lowercase. Use the below syntax:
// Consider the below example
originalString.replace(/stringToBeReplaced/gi, '');
// The output will be all the occurrences removed irrespective of casing.
You can refer to the detailed example here.
If you are trying to ensure that the string you are looking for won't exist even after the replacement, you need to use a loop.
For example:
var str = 'test aabcbc';
str = str.replace(/abc/g, '');
When complete, you will still have 'test abc'!
The simplest loop to solve this would be:
var str = 'test aabcbc';
while (str != str.replace(/abc/g, '')){
str.replace(/abc/g, '');
}
But that runs the replacement twice for each cycle. Perhaps (at risk of being voted down) that can be combined for a slightly more efficient but less readable form:
var str = 'test aabcbc';
while (str != (str = str.replace(/abc/g, ''))){}
// alert(str); alerts 'test '!
This can be particularly useful when looking for duplicate strings.
For example, if we have 'a,,,b' and we wish to remove all duplicate commas.
[In that case, one could do .replace(/,+/g,','), but at some point the regex gets complex and slow enough to loop instead.]
My implementation, very self explanatory
function replaceAll(string, token, newtoken) {
if(token!=newtoken)
while(string.indexOf(token) > -1) {
string = string.replace(token, newtoken);
}
return string;
}
You can simply use below method
/**
* Replace all the occerencess of $find by $replace in $originalString
* @param {originalString} input - Raw string.
* @param {find} input - Target key word or regex that need to be replaced.
* @param {replace} input - Replacement key word
* @return {String} Output string
*/
function replaceAll(originalString, find, replace) {
return originalString.replace(new RegExp(find, 'g'), replace);
};
The following function works for me:
String.prototype.replaceAllOccurence = function(str1, str2, ignore)
{
return this.replace(new RegExp(str1.replace(/([\/\,\!\\\^\$\{\}\[\]\(\)\.\*\+\?\|\<\>\-\&])/g,"\\$&"),(ignore?"gi":"g")),(typeof(str2)=="string")?str2.replace(/\$/g,"$$$$"):str2);
} ;
Now call the functions like this:
"you could be a Project Manager someday, if you work like this.".replaceAllOccurence ("you", "I");
Simply copy and paste this code in your browser console to TEST.
I use split and join or this function:
function replaceAll(text, busca, reemplaza) {
while (text.toString().indexOf(busca) != -1)
text = text.toString().replace(busca, reemplaza);
return text;
}
There is now a finished proposal for integrating String.prototype.replaceAll
into the official specification. Eventually, developers will not have to come up with their own implementations for replaceAll
- instead, modern JavaScript engines will support it natively.
The proposal is at stage 4, which means that everything is complete, and all that's left is for browsers to start implementing it.
It has shipped in the latest versions of Chrome, Firefox, and Safari.
Here are the implementation details:
Per the current TC39 consensus,
String.prototype.replaceAll
behaves identically toString.prototype.replace
in all cases, except for the following two cases:
- If
searchValue
is a string,String.prototype.replace
only replaces a single occurrence of thesearchValue
, whereasString.prototype.replaceAll
replaces all occurrences of thesearchValue
(as if.split(searchValue).join(replaceValue)
or a global & properly-escaped regular expression had been used).- If
searchValue
is a non-global regular expression,String.prototype.replace
replaces a single match, whereasString.prototype.replaceAll
throws an exception. This is done to avoid the inherent confusion between the lack of a global flag (which implies "do NOT replace all") and the name of the method being called (which strongly suggests "replace all").Notably,
String.prototype.replaceAll
behaves just likeString.prototype.replace
ifsearchValue
is a global regular expression.
You can see a specification-compliant polyfill here.
In supported environments, the following snippet will log foo-bar-baz
, without throwing an error:
const str = 'foo bar baz';
console.log(
str.replaceAll(' ', '-')
);
If using a library is an option for you then you will get the benefits of the testing and community support that goes with a library function. For example, the string.js library has a replaceAll() function that does what you're looking for:
// Include a reference to the string.js library and call it (for example) S.
str = S(str).replaceAll('abc', '').s;
In my applications, I use a custom function that is the most powerful for this purpose, and even wrapping the split/join
solution in the simpler case, it is a little bit faster in Chrome 60 and Firefox 54 (JSBEN.CH) than other solutions. My computer runs Windows 7 64 bits.
The advantage is that this custom function can handle many substitutions at the same time using strings or characters, which can be a shortcut for some applications.
Like the above split/join solution, the solution below doesn't have any problems with escape characters, differently than the regular expression approach.
function replaceAll(s, find, repl, caseOff, byChar) {
if (arguments.length<2)
return false;
var destDel = ! repl; // If destDel delete all keys from target
var isString = !! byChar; // If byChar, replace set of characters
if (typeof find !== typeof repl && ! destDel)
return false;
if (isString && (typeof find !== "string"))
return false;
if (! isString && (typeof find === "string")) {
return s.split(find).join(destDel ? "" : repl);
}
if ((! isString) && (! Array.isArray(find) ||
(! Array.isArray(repl) && ! destDel)))
return false;
// If destOne replace all strings/characters by just one element
var destOne = destDel ? false : (repl.length === 1);
// Generally source and destination should have the same size
if (! destOne && ! destDel && find.length !== repl.length)
return false
var prox, sUp, findUp, i, done;
if (caseOff) { // Case insensitive
// Working with uppercase keys and target
sUp = s.toUpperCase();
if (isString)
findUp = find.toUpperCase()
else
findUp = find.map(function(el) {
return el.toUpperCase();
});
}
else { // Case sensitive
sUp = s;
findUp = find.slice(); // Clone array/string
}
done = new Array(find.length); // Size: number of keys
done.fill(null);
var pos = 0; // Initial position in target s
var r = ""; // Initial result
var aux, winner;
while (pos < s.length) { // Scanning the target
prox = Number.MAX_SAFE_INTEGER;
winner = -1; // No winner at the start
for (i=0; i<findUp.length; i++) // Find next occurence for each string
if (done[i]!==-1) { // Key still alive
// Never search for the word/char or is over?
if (done[i] === null || done[i] < pos) {
aux = sUp.indexOf(findUp[i], pos);
done[i] = aux; // Save the next occurrence
}
else
aux = done[i] // Restore the position of last search
if (aux < prox && aux !== -1) { // If next occurrence is minimum
winner = i; // Save it
prox = aux;
}
} // Not done
if (winner === -1) { // No matches forward
r += s.slice(pos);
break;
} // No winner
// Found the character or string key in the target
i = winner; // Restore the winner
r += s.slice(pos, prox); // Update piece before the match
// Append the replacement in target
if (! destDel)
r += repl[destOne ? 0 : i];
pos = prox + (isString ? 1 : findUp[i].length); // Go after match
} // Loop
return r; // Return the resulting string
}
The documentation is below:
replaceAll Syntax ====== replaceAll(s, find, [repl, caseOff, byChar) Parameters ========== "s" is a string target of replacement. "find" can be a string or array of strings. "repl" should be the same type than "find" or empty If "find" is a string, it is a simple replacement for all "find" occurrences in "s" by string "repl" If "find" is an array, it will replaced each string in "find" that occurs in "s" for corresponding string in "repl" array. The replace specs are independent: A replacement part cannot be replaced again. If "repl" is empty all "find" occurrences in "s" will be deleted. If "repl" has only one character or element, all occurrences in "s" will be replaced for that one. "caseOff" is true if replacement is case insensitive (default is FALSE) "byChar" is true when replacement is based on set of characters. Default is false If "byChar", it will be replaced in "s" all characters in "find" set of characters for corresponding character in "repl" set of characters Return ====== The function returns the new string after the replacement.
To be fair, I ran the benchmark with no parameter test.
Here is my test set, using Node.js:
function l() {
return console.log.apply(null, arguments);
}
var k = 0;
l(++k, replaceAll("banana is a ripe fruit harvested near the river",
["ri", "nea"], ["do", "fa"])); // 1
l(++k, replaceAll("banana is a ripe fruit harvested near the river",
["ri", "nea"], ["do"])); // 2
l(++k, replaceAll("banana is a ripe fruit harvested near the river",
["ri", "nea"])); // 3
l(++k, replaceAll("banana is a ripe fruit harvested near the river",
"aeiou", "", "", true)); // 4
l(++k, replaceAll("banana is a ripe fruit harvested near the river",
"aeiou", "a", "", true)); // 5
l(++k, replaceAll("banana is a ripe fruit harvested near the river",
"aeiou", "uoiea", "", true)); // 6
l(++k, replaceAll("banana is a ripe fruit harvested near the river",
"aeiou", "uoi", "", true)); // 7
l(++k, replaceAll("banana is a ripe fruit harvested near the river",
["ri", "nea"], ["do", "fa", "leg"])); // 8
l(++k, replaceAll("BANANA IS A RIPE FRUIT HARVESTED NEAR THE RIVER",
["ri", "nea"], ["do", "fa"])); // 9
l(++k, replaceAll("BANANA IS A RIPE FRUIT HARVESTED NEAR THE RIVER",
["ri", "nea"], ["do", "fa"], true)); // 10
return;
And the results:
1 'banana is a dope fruit harvested far the dover'
2 'banana is a dope fruit harvested dor the dover'
3 'banana is a pe fruit harvested r the ver'
4 'bnn s rp frt hrvstd nr th rvr'
5 'banana as a rapa fraat harvastad naar tha ravar'
6 'bununu is u ripo frait hurvostod nour tho rivor'
7 false
8 false
9 'BANANA IS A RIPE FRUIT HARVESTED NEAR THE RIVER'
10 'BANANA IS A doPE FRUIT HARVESTED faR THE doVER'
In November 2019, a new feature is added to the JavaScript, string.prototype.replaceAll()
.
Currently it's only supported with Babel, but maybe in the future it can be implemented in all the browsers. For more information, read here.
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aba
inababa
withca
, which result do you expect?caba
?abca
?cca
? – reinierpost Commented Aug 2, 2019 at 12:58String.prototype.replaceAll()
is now a standard part of ECMAScript tc39.es/ecma262/#sec-string.prototype.replaceall, documented at developer.mozilla.org/docs/Web/JavaScript/Reference/… and shipped in Safari 13.1, Firefox 77 and Chrome Dev/Canary and will ship in Chrome 85. From the docs: “If searchValue is a string, replaces all occurrences of searchValue (as if.split(searchValue).join(replaceValue)
or a global & properly-escaped regular expression had been used). If searchValue is a non-global regular expression, throws an exception” – sideshowbarker ♦ Commented Jun 29, 2020 at 5:26