Mocha: TypeError: Converting circular structure to JSON

Question

Mocha suddenly is throwing

TypeError: Converting circular structure to JSON

I have done a new setup for executing the test cases. The test cases were running fine till yesterday. I am using: Mocha, Chai, Sinon, Enzyme

This is my package.json:

{
      "name": "abc",
      "version": "1.0.0",
      "description": "desc",
      "scripts": {
        "build": "webpack --config webpack-client.config.js",
        "devbuild": "webpack --config webpack-client-dev.config.js",
        "test": "mocha --compilers js:babel-register --require ./test/dom.js --require ./test/helpers.js  --recursive",
        "tdd": "npm test -- --watch",
        "coverage": "nyc --reporter=html --reporter=text npm test"
      },
      "repository": {
        "type": "git",
        "url": ""
      },
      "author": "author",
      "license": "ISC",
      "devDependencies": {
        "babel-core": "^6.0.0",
        "babel-loader": "^6.0.0",
        "babel-preset-es2015": "^6.24.1",
        "chai": "^4.0.2",
        "compression-webpack-plugin": "^0.3.2",
        "coveralls": "^2.13.1",
        "enzyme": "^2.9.0",
        "istanbul": "^0.4.5",
        "jquery": "^3.2.1",
        "jsdom": "11.0.0",
        "jsdom-global": "3.0.2",
        "mocha": "3.2.0",
        "nyc": "^11.0.3",
        "react-addons-test-utils": "^15.6.0",
        "sinon": "^2.3.5",
        "webpack": "^1.12.2",
        "webpack-bundle-analyzer": "^2.3.1"
      },
      "dependencies": {
        "exenv": "^1.2.1",
        "expose-loader": "^0.7.0",
        "flux": "2.0.1",
        "html-webpack-plugin": "^2.28.0",
        "htmlescape": "1.0.0",
        "intl": "^1.2.5",
        "intl-locales-supported": "^1.0.0",
        "keymirror": "^0.1.1",
        "morgan": "1.5.2",
        "object-assign": "^4.1.1",
        "prop-types": "^15.5.4",
        "react": "^15.4.2",
        "react-bootstrap": "^0.31.0",
        "react-dom": "^15.4.2",
        "react-intl": "^2.0.0-beta-2",
        "react-toastr": "^2.8.2",
        "zxcvbn": "^4.4.2"
      }
    }

Please find the error thrown on the console : Please help. Thank you

We have no idea why your code is breaking if you don't actually post it. The stack trace that accompanies the error should provide some clues where the error originates from. — robertklep, Jul 03 '17 at 15:51
Did you ever find out what the issue was? Having the same problem, with a setup that works on other projects. — joshea, Oct 30 '17 at 19:56
Not really....i deleted the node_modules folder, revisited the package.js json and removed the unwanted dependencies i had in my package.json related to the unit testing setup which i had added while i was doing the initial setup. So i guess an unwanted package was creating a problem. — Soham Nakhare, Nov 05 '17 at 10:14

score 1 · Answer 1 · answered Oct 05 '22 at 20:55

I ran into this. Based on googling around, there seem to be many different causes for this. Here's my situation: I'm using mocha with chai and ts-node/register to run TypeScript test files directly (without needing to transpile them myself).

My solution was this:

Add import {describe, it} from 'mocha'; at the top of my TS test files.

I've never had to do this before and I have no idea why I suddenly need to add them now. But it is what it is.

Mocha: TypeError: Converting circular structure to JSON

1 Answers1