How to replace all occurrences of a string?

javascript string replace
Click Upvote picture Click Upvote · Jul 17, 2009 · Viewed 3.6M times · Source

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

Sean Bright picture Sean Bright · Jul 17, 2009

As of August 2020, greenfield browsers have support for the String.replaceAll() method defined by the ECMAScript 2021 language specification. For older/legacy browser support, the below still applies.

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 (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);
}

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