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How to Solve the replaceAll error in Jest?

·1 min

One time I was working on a legacy React project, I ran a recently added unit test and I got this error:

Problem

Jest: TypeError: replaceAll is not a function

I was confused at the beginning because in the browser the component was working like a charm using replaceAll method, but it turns out that replaceAll is a new function not implemented in all browsers nor older Node.js versions.

Solution

Install the replaceAll polyfill and add it to the jest setup configuration file.
  1. Install the replaceAll
npm i string.prototype.replaceall
  1. Modify your Jest config, add a setupFilesAfterEnv property as below:
{
  "jest": {
    "setupFilesAfterEnv": ["<rootDir>/jestSetup.js"]
  }
}
  1. Add the following code to your jestSetup file
import replaceAllInserter from 'string.prototype.replaceall';

replaceAllInserter.shim();

Happy coding!

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