How do I replace all occurrences of a string in JavaScript?

To replace all occurrences of a string in JavaScript, you can use the replace() method with a regular expression.

Here's how you can do it:

let s = "Test abc test test abc test test test abc test test abc";

// Replace all occurrences of 'abc' with an empty string
s = s.replace(/abc/g, '');

console.log(s); // Output: "Test  test test  test test test  test test "

Explanation:

1. The replace() method takes two arguments: the pattern to search for and the replacement string.
2. In this case, the pattern is /abc/g, which is a regular expression that matches all occurrences of the string "abc".
3. The g flag in the regular expression stands for "global", which means that the replacement will be done for all matches, not just the first one.
4. The replacement string is an empty string '', which means that all occurrences of "abc" will be removed from the original string.

You can also use the replaceAll() method, which was introduced in ECMAScript 2021 (ES12) and provides a more concise way to replace all occurrences of a string:

let s = "Test abc test test abc test test test abc test test abc";

// Replace all occurrences of 'abc' with an empty string
s = s.replaceAll('abc', '');

console.log(s); // Output: "Test  test test  test test test  test test "

The replaceAll() method works the same way as the replace() method with the global flag (/abc/g), but it's more readable and easier to use.

To replace all occurrences of a substring within a string in JavaScript, you can use the replace() method with a regular expression that includes the global flag (g). Here's how you can modify your code:

let s = "Test abc test test abc test test test abc test test abc";
s = s.replace(/abc/g, '');
console.log(s);

Output:

Test  test test  test test test  test test 

Explanation:

• The replace() method takes two arguments: the first argument is the substring or regular expression to search for, and the second argument is the replacement string.
• In this case, instead of using a simple string as the first argument, we use a regular expression /abc/g. The forward slashes (/) delimit the regular expression, and the g flag at the end indicates that we want to perform a global replacement (i.e., replace all occurrences).
• By using a regular expression with the global flag, the replace() method will find and replace all occurrences of the specified substring ('abc') with the replacement string ('', an empty string in this case).

So, the resulting string s will have all occurrences of 'abc' removed.

Note that the regular expression can be modified to match different patterns or substrings based on your specific requirements. For example, if you want to perform a case-insensitive replacement, you can add the i flag along with the g flag, like this: /abc/gi.

I hope this helps! Let me know if you have any further questions.

In JavaScript, the replace() method by default only replaces the first occurrence of a matched substring. To replace all occurrences, you can use a regular expression with the global (g) flag.

Here's how you can replace all occurrences of abc in the given string:

s = "Test abc test test abc test test test abc test test abc";
s = s.replace(/abc/g, '');

console.log(s);
// Output: "Test  test  test  test  test  test  test  test  "

In this example, I created a regular expression (/abc/g) using forward slashes and the g flag for global search. Then, I passed it to the replace() method to replace all occurrences of abc.

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:

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.

To replace all occurrences of a string in JavaScript, you can use the replace() method with a regular expression and the global flag (/g). Here's how you can do it:

let s = "Test abc test test abc test test test abc test test abc";
s = s.replace(/abc/g, '');
console.log(s); // Output: "Test   test test   test test test   test test  "

In this example, we use the regular expression /abc/g to match all occurrences of the string "abc" in the input string. The g flag stands for "global" and ensures that the replace() method replaces all occurrences, not just the first one.

If you want to replace "abc" with another string instead of an empty string, you can pass the replacement string as the second argument to the replace() method:

let s = "Test abc test test abc test test test abc test test abc";
s = s.replace(/abc/g, 'xyz');
console.log(s); // Output: "Test xyz test test xyz test test test xyz test test xyz"

In this case, all occurrences of "abc" are replaced with "xyz".

Here's a step-by-step breakdown of how the replace() method with a regular expression works:

1. The regular expression /abc/g is created, where:
   • /abc/ is the pattern to match (in this case, the string "abc")
   • g is the global flag that ensures all occurrences are replaced
2. The replace() method is called on the input string s.
3. The regular expression /abc/g is used to find all occurrences of "abc" in the string.
4. Each occurrence of "abc" is replaced with the provided replacement string (an empty string '' in the first example, or 'xyz' in the second example).
5. The modified string is returned and assigned back to the variable s.

Using regular expressions with the global flag is a powerful way to perform string replacements in JavaScript, as it allows you to replace patterns, not just literal strings. This approach is particularly useful when you need to replace more complex patterns or when you need to apply additional modifiers or flags to the regular expression.

To replace all occurrences of a string in JavaScript, you can use the replace() method with a regular expression. Here's an example:

const s = "Test abc test test abc test test test abc test test abc";

const replacementString = "new_string";

const result = s.replace(/abc/, replacementString);

console.log(result); // Output: "Test new_string test test new_string test test new_string test test abc"

Explanation:

• replace(/abc/, replacementString) uses a regular expression abc to match any occurrence of abc in the string.
• replacementString specifies the string that should replace the match.
• s.replace() performs the replacement and returns the resulting string.

Note:

• The regular expression abc assumes that abc is a substring in the string.
• If you want to replace the first occurrence only, use replace(0, "new_string").
• replace() also supports multiple occurrences by passing an array of strings as the replacement.

Other alternatives:

• Use s.split() and s.join() to split the string and then join it back with the replacement.
• Use the replaceAll method for a single replacement across all occurrences.

Choose the approach that best suits your coding style and preference.

To replace all occurrences of a string in JavaScript, you can use the replaceAll() method. Here's how you can do it:

s = s.replaceAll('abc', '');

This will replace all occurrences of the substring "abc" with an empty string, effectively removing them from the string.

To replace all occurrences of a string in JavaScript, you can use the global g flag in the replace() method:

s = "Test abc test test abc test test test abc test test abc";

s = s.replace(/abc/g, '');

console.log(s); // Output: "Test test test test test test test test test"

The g flag makes the replace() method replace all occurrences of the given string with the replacement string.

You can use the g flag in your regular expression to replace all occurrences of a string in JavaScript. Here is an example of how you can do this:

let s = "Test abc test test abc test test test abc test test abc";
s = s.replace(/abc/g, '');
console.log(s); // Output: "Test  test  test  test  test"

The /g flag at the end of the regular expression tells JavaScript to replace all occurrences of abc in the string, rather than just the first one. The '' empty string is used as the replacement value to indicate that the matches should be removed from the string.

Note that this approach will only work if the abc you are trying to replace is a standalone string and not part of another larger string. If you have a larger string that contains multiple instances of abc, you may need to use a different approach to replace all occurrences.

In JavaScript, the replace method with one argument will only replace the first occurrence of the given substring in a string. To replace all occurrences, you need to use a regular expression with the g flag (short for "global"). Here is how you can do it:

s = s.replace(/abc/g, 'newString');

Replace abc with your search string and newString with the replacement string. This will replace all occurrences of the given string in your input s.

Modern browsers have support for the String.replaceAll() method defined by the ECMAScript 2021 language specification.

function escapeRegExp(string) {
  return string.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);
}

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);
}

In JavaScript replace() function works only for replacing one instance of a string in another. If you want to replace all instances, then you would have to call this method recursively. Here's how to achieve that using a while loop and your current method inside it. This will continue until there are no more occurrences left to replace:

var s = "Test abc test test abc test test test abc test test abc"; 
while (true) { 
    if (s === (s=s.replace('abc', ''))) break; 
} 
console.log(s); // it will log: Test  test test  test test  test abc test test abc

This way we've effectively replaced all occurrences of 'abc'. Please note, this method might not work in every situation because strings can contain a sequence like "abcd" which is not what you want to replace. For such situations the Regular expressions or other methods should be used for substitution.

To replace all occurrences of a substring in JavaScript, you can use the replace() method with a loop. Here's an example code snippet that will replace all instances of 'hello' with 'hi' and return the new string:

let s = "Hello World!"; // String to modify 

for (var i = 0; i < s.length; i++) { // Loop through each character in the string
    if (s.charAt(i) == 'h') { // Check if this is a capital 'H'
        s = s.substring(0,i) + "hi" + s.substr(i+1); // Replace this substring with 'hello' in all cases. 
    } else if (s.charAt(i) == 'l') { // Check if this is a lowercase 'L'.
        s = s.substring(0,i) + "li" + s.substr(i+1); // Replace this substring with 'hi' in all cases. 
    } else if (s.charAt(i) == 'o') { // Check if this is a capital 'O'.
        s = s.substring(0,i) + "lo" + s.substr(i+1); // Replace this substring with 'li' in all cases. 
    } else if (s.charAt(i) == 'r') { // Check if this is a lowercase 'R'.
        s = s.substring(0,i) + "ro" + s.substr(i+1); // Replace this substring with 'lo' in all cases. 
    } else if (s.charAt(i) == 'y') { // Check if this is a lowercase 'Y'.
        s = s.substring(0,i) + "ye" + s.substr(i+1); // Replace this substring with 'lo' in all cases. 
    } else if (s.charAt(i) == 'T') { // Check if this is a lowercase 't'.
        s = s.substring(0,i) + "ti" + s.substr(i+1); // Replace this substring with 'lo' in all cases. 
    } else if (s.charAt(i) == 'h') { // Check if this is a lowercase 'H'.
        s = s.substring(0,i) + "he" + s.substr(i+1); // Replace this substring with 'hi' in all cases. 
    } else if (s.charAt(i) == 'e') { // Check for a capital 'E'.
        s = s.substring(0,i) + "ee" + s.substr(i+1); // Replace this substring with 'hi' in all cases. 
    } else if (s.charAt(i) == 'x') { // Check for a capital X.
        s = s.substring(0,i) + "ix" + s.substr(i+1); // Replace this substring with 'li' in all cases. 
    } else if (s.charAt(i) == 'x') { // Check for a lowercase 'X'.
        s = s.substring(0,i) + "ix" + s.substr(i+1); // Replace this substring with 'li' in all cases. 
    } else if (s.charAt(i) == 'z') { // Check for a lowercase Z.
        s = s.substring(0,i) + "zee" + s.substr(i+1); // Replace this substring with 'li' in all cases. 
    } else if (s.charAt(i) == 'z') { // Check for a lowercase Z.
        s = s.substring(0,i) + "zi" + s.substr(i+1); // Replace this substring with 'lo' in all cases. 
    } else if (s.charAt(i) == '1') { // Check for a capital 1.
        s = s.substring(0,i) + "e" + s.substr(i+1); // Replace this substring with 'hi' in all cases. 
    } else if (s.charAt(i) == '2') { // Check for a lowercase 2.
        s = s.substring(0,i) + "e" + s.substr(i+1); // Replace this substring with 'lo' in all cases. 
    } else if (s.charAt(i) == '3') { // Check for a lowercase 3.
        s = s.substring(0,i) + "e" + s.substr(i+1); // Replace this substring with 'lo' in all cases. 
    } else if (s.charAt(i) == '4') { // Check for a lowercase 4.
        s = s.substring(0,i) + "e" + s.substr(i+1); // Replace this substring with 'lo' in all cases. 
    } else if (s.charAt(i) == '5') { // Check for a lowercase 5.
        s = s.substring(0,i) + "e" + s.substr(i+1); // Replace this substring with 'lo' in all cases. 
    } else if (s.charAt(i) == '6') { // Check for a lowercase 6.
        s = s.substring(0,i) + "e" + s.substr(i+1); // Replace this substring with 'lo' in all cases. 
    } else if (s.charAt(i) == '7') { // Check for a lowercase 7.
        s = s.substring(0,i) + "e" + s.substr(i+1); // Replace this substring with 'lo' in all cases. 
    } else if (s.charAt(i) == '8') { // Check for a lowercase 8.
        s = s.substring(0,i) + "e" + s.substr(i+1); // Replace this substring with 'lo' in all cases. 
    } else if (s.charAt(i) == '9') { // Check for a lowercase 9.
        s = s.substring(0,i) + "e" + s.substr(i+1); // Replace this substring with 'lo' in all cases. 
    } else if (s.charAt(i) == 'A') { // Check for a capital A.
        s = s.substring(0,i) + "he" + s.substr(i+1); // Replace this substring with 'hi' in all cases. 
    } else if (s.charAt(i) == 'B') { // Check for a lowercase B.
        s = s.substring(0,i) + "he" + s.substr(i+1); // Replace this substring with 'lo' in all cases. 
    } else if (s.charAt(i) == 'C') { // Check for a capital C.
        s = s.substring(0,i) + "ch" + s.substr(i+1); // Replace this substring with 'hi' in all cases. 
    } else if (s.charAt(i) == 'D') { // Check for a lowercase D.
        s = s.substring(0,i) + "dh" + s.substr(i+1); // Replace this substring with 'lo' in all cases. 
    } else if (s.charAt(i) == 'E') { // Check for a lowercase E.
        s = s.substring(0,i) + "ee" + s.substr(i+1); // Replace this substring with 'hi' in all cases. 
    } else if (s.charAt(i) == '9') { // Check for a lowercase 9.
        s = "".fromfromfromtofromfromtofromtoimport/fromwith
     } else if (s.lower() == 'f') { // Check with 3.
    

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To replace all occurrences of a string in JavaScript, you can use the replace method with the {0, times=无穷}} pattern to match all occurrences of the string. Here's an example:

const str = "Test abc test test abc test test test abc";
const newStr = str.replace("abc", "");
console.log(newStr);  // Output: Test test test test

In this example, we first define a variable str with the original string. We then use the replace method to match all occurrences of the substring "abc" within the original string, and replace them with an empty string " ". Finally, we assign the new string to another variable newStr, which we then output using the console.log function.