How to replace all occurrences of a string?

Question

I have this string:

"Test abc test test abc test test test abc test test abc"

Doing:

str = str.replace('abc', '');

seems to only remove the first occurrence of abc in the string above.

How can I replace all occurrences of it?

Answer 1

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

In response to comment:

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:

function escapeRegExp(str) {
    return str.replace(/([.*+?^=!:${}()|\[\]\/\\])/g, "\\$1");
}

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);
}

Answer 2

Match against a global regular expression:

anotherString = someString.replace(/cat/g, 'dog');

Answer 3

Using RegExp in JavaScript could do the job for you, just simply do something like below code, don't forget the /g after which standout for global:

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

If you think of reuse, create a function to do that for you, but it's not recommended as it's only one line function, but again if you heavily use this, you can write something like this:

String.prototype.replaceAll = String.prototype.replaceAll || function(string, replaced) {
  return this.replace(new RegExp(string, 'g'), replaced);
};

and simply use it in your code over and over like below:

var str ="Test abc test test abc test test test abc test test abc";
str = str.replaceAll('abc', '');

But as I mention earlier, it won't make a huge difference in terms of lines to be written or performance, only caching the function may effect some faster performance on long strings and also a good practice of DRY code if you want to reuse.

Answer 4

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);
};

Answer 5

//loop it until number occurrences comes to 0. OR simply copy/paste

    function replaceAll(find, replace, str) 
    {
      while( str.indexOf(find) > -1)
      {
        str = str.replace(find, replace);
      }
      return str;
    }

Answer 6

var str = "ff ff f f a de def";
str = str.replace(/f/g,'');
alert(str);

http://jsfiddle.net/ANHR9/