How to use Jest to test functions using crypto or window.msCrypto

Like @RwwL, the accepted answer did not work for me. I found that the polyfill used in this library did work: commit with polyfill

//setupTests.tsx
const nodeCrypto = require('crypto');
window.crypto = {
  getRandomValues: function (buffer) {
    return nodeCrypto.randomFillSync(buffer);
  }
};

//jest.config.js
module.exports = {
 //...
  setupFilesAfterEnv: ["<rootDir>/src/setupTests.tsx"],
};

Since node 15.x you can use crypto.webcrypto

eg.

import crypto from "crypto";

Object.defineProperty(global.self, "crypto", {
  value: {
    subtle: crypto.webcrypto.subtle,
  },
});

For nodeJS + typescript, just use global instead of global.self

import crypto from 'crypto'

Object.defineProperty(global, 'crypto', {
  value: {
    getRandomValues: (arr:any) => crypto.randomBytes(arr.length)
  }
});

This should do it. Use the following code to set up the crypto property globally. This will allow Jest to access window.crypto and won't cause any issue.

const crypto = require('crypto');

Object.defineProperty(global.self, 'crypto', {
  value: {
    getRandomValues: arr => crypto.randomBytes(arr.length)
  }
});