Replace all

Currently, there are two ‘workarounds’ to replace all string occurrences in JavaScript, and the ‘new’ replaceAll method.

The workarounds

With the split method and a search value, divide the string into a list of substrings
Create a new string, with the join method, by concatenating the above substrings with the replacement value in between

Example:

const newString = ‘foo bat bat’.split(‘bat’).join(‘bar’);

The first part: foo bat bat’.split(‘bat’) returns

Then, when we apply .join(‘bar’) we get a new string:

The method replace() receives two parameters, a search value to look for and a replacement value.

Create a regular expression (this is the search value) and append it the global flag g:
- /search value/g
- RegExp(‘search value’, ‘g’)
Replace the occurrences with the replacement value.

Example:

const newString = ‘foo bat bat’.replace(/bat/g, ‘bar’);

const newString ='foo bat bat'.replace(RegExp('bat', 'g'), ‘bar');

Right now, it is at stage 4 of the TC39 process.

The committee that governs how ECMAScript features are designed.
There are five stages (0 to 4) to make changes in the language: Straw, Proposal, Draft, Candidate, and Finished.
- https://tc39.es/process-document/
- https://github.com/tc39/proposal-string-replaceall

String.prototype.replaceAll()

It searches a string for value or regex.
The method returns a new string with all matches of a pattern replaced by a replacement.
It behaves identically as the replace() method, with two exceptions, see:
- https://github.com/tc39/proposal-string-replaceall/blob/master/README.md
- https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/replaceAll

Example:

const newString = ‘foo bat bat’.replaceAll(‘bat’, ‘bar’);

Looking for regex in *.js files (a subset from the NPM library)

Total number of replacements found: 386

Field	Total	Field	Total
Backreferences in the search value	0, = 0%	split() and join() methods	59, ~ 15.28%
Backreferences in the replacement value	47, ~ 12.18%	replace() method and g flag	327, ~ 84.72%
Others	~ 87.82%	replaceAll():	0, = 0%

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