[SOLVED] "ReferenceError: structuredClone is not defined" using jest with nodejs & typescript

"ReferenceError: structuredClone is not defined" using jest with nodejs & typescript

I'm running tests with jest in a simple NodeJS app that uses typescript. My test is throwing an error: ReferenceError: structuredClone is not defined.

I'm not getting any linter errors and the code compiles fine normally.

  const variableForValidation = structuredClone(variableForValidationUncloned);

package.json:

  "dependencies": {
    ...
  },
  "devDependencies": {
    "@types/jest": "^29.0.0",
    "@types/node": "^18.7.15",
    "@typescript-eslint/eslint-plugin": "^5.36.1",
    "@typescript-eslint/parser": "^5.36.1",
    "eslint": "^8.23.0",
    "jest": "^28.0.1",
    "nodemon": "^2.0.19",
    "serverless-plugin-typescript": "^2.1.2",
    "ts-jest": "^28.0.8",
    "ts-node": "^10.9.1",
    "typescript": "^4.8.2"
  }

This github issue suggests to me that the issue has been resolved: https://github.com/facebook/jest/issues/12628 - or perhaps I'm misunderstanding?

I've seen a similar Stack question but using Mocha: mocha not recognizing structuredClone is not defined

Solution

structuredClone was added in Node 17.

If you can't update, the JSON hack (stringify then parse) works, but has some shortcomings that might be relevant to you:

Recursive data structures: JSON.stringify() will throw when you give it a recursive data structure. This can happen quite easily when working with linked lists or trees.

Built-in types: JSON.stringify() will throw if the value contains other JS built-ins like Map, Set, Date, RegExp or ArrayBuffer.

Functions: JSON.stringify() will quietly discard functions.

Edit:

I recently learned about the json-stringify-safe, that helps with the circular issue.