How does FreeCodeCamp run/test our code

damod.d77 · February 11, 2023, 4:22am

How does FreeCodeCamp run/test our code. Does it run it in the backend? Does it run it inside the browser itself? I am trying to build something similar to the code runner so this information would help a lot. Thanks

Clement-Othniel · February 11, 2023, 4:56am

I think it is run in the backend

Sky020 · February 11, 2023, 1:41pm

Welcome there,

All of freeCodeCamp’s code is publicly visible and open-source:

The tests are run in different ways depending on which challenge you are referring to.

Most of the tests are simple Chaijs assertions running in the browser:

github.com

freeCodeCamp/freeCodeCamp/blob/main/client/src/client/workers/test-evaluator.ts

import chai from 'chai';
import '@babel/polyfill';
import { toString as __toString } from 'lodash-es';
import * as helpers from '@freecodecamp/curriculum-helpers';
import { format as __format } from '../../utils/format';

const ctx: Worker & typeof globalThis = self as unknown as Worker &
  typeof globalThis;

const __utils = (() => {
  const MAX_LOGS_SIZE = 64 * 1024;

  let logs: string[] = [];
  function flushLogs() {
    if (logs.length) {
      ctx.postMessage({
        type: 'LOG',
        data: logs.join('\n')
      });
      logs = [];

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Hope this helps