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

When running unit tests with Jest in react the window.crypto API is causing problems. I haven’t found a way to incorporate crypto in Jest without installing other packages which is something I can’t do. So without using another npm package is there a way to test functions that use: crypto.getRandomValues() in them that doesn’t crash Jest? Any links, advice, or tips are appreciated

Answer

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)
  }
});

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