Jest JSON Reporter

1.2.2 · active · verified Sun Apr 19

jest-json-reporter is a utility package for Jest that processes test results and outputs them to a specified JSON file. It adheres to the JSON format defined by Jest's own documentation, making it suitable for integration into Continuous Integration (CI) pipelines, custom reporting dashboards, or any system that consumes structured test results. The package is currently at version 1.2.2 and generally operates as a 'set-and-forget' utility, meaning its release cadence is typically slow, focused on stability and compatibility with new Jest versions rather than frequent feature additions. Its key differentiator is its straightforward, minimal configuration for generating a standard JSON report, which is often preferred over more complex or opinionated reporting solutions when raw data is needed for further processing.

Common errors

```
Cannot find module './node_modules/jest-json-reporter' from 'package.json'
```
cause Jest could not resolve the specified path for the test results processor, likely due to a typo, incorrect path, or the package not being installed.

fix Verify that `jest-json-reporter` is installed (check `node_modules` and `package.json`). Ensure the path in `testResultsProcessor` is exactly `./node_modules/jest-json-reporter`.
```
Jest: No tests found, exiting with error code 1
```
cause This error itself isn't directly from `jest-json-reporter`, but if Jest isn't configured correctly to find tests, the reporter won't have any results to process, leading to confusion about its operation.

fix Ensure your Jest configuration (`testMatch`, `testRegex`) correctly identifies your test files. The `jest-json-reporter` will only output results if Jest actually runs tests.

Warnings

breaking Major Jest version updates (e.g., Jest v27, v28, v29+) can sometimes introduce changes to the reporter API or how modules are resolved (e.g., ESM vs. CJS). While generally stable, ensure compatibility by testing against new Jest versions before upgrading in production.
Fix: Consult the `jest-json-reporter` GitHub repository for specific version compatibility notes or open an issue if an incompatibility arises. Pin Jest versions if necessary.
gotcha The `testResultsProcessor` path in `package.json` or `jest.config.js` must be correct and resolvable from the project root. Incorrect relative paths or typos will lead to Jest failing to load the reporter.
Fix: Always use a path relative to your project's root (e.g., `./node_modules/jest-json-reporter`) or an absolute path. Double-check for typos.
gotcha The `outputFile` configuration determines where the JSON results are written. If not configured, it defaults to `test-results.json` in the project root. Using a non-unique or shared `outputFile` path across different test runs or CI stages can lead to files being overwritten.
Fix: Configure a unique `outputFile` name and path, especially in CI environments where multiple jobs might run in parallel or where results need to be archived distinctly. For example, `outputFile: 'reports/jest-results-${process.env.CI_JOB_ID || Date.now()}.json'`.

Install

npm install jest-json-reporter npm
yarn add jest-json-reporter yarn
pnpm add jest-json-reporter pnpm

Imports

JestJSONReporterPath
wrong:
```
import reporter from 'jest-json-reporter';
```
correct:
```
"testResultsProcessor": "./node_modules/jest-json-reporter"
```
jest-json-reporter is not directly imported into application code. Instead, it is configured within Jest's `package.json` or `jest.config.js` via a string path, which Jest then uses to load the CommonJS module at runtime. The 'symbol' refers to the module path itself as Jest's configuration entry point. Direct `import` or `require` in user code is not the intended usage.

Quickstart

Demonstrates how to install jest-json-reporter, configure it in package.json, run Jest with a basic test, and verify the generated JSON output file.

npm install --save-dev jest jest-json-reporter

// package.json
// Add the following configuration to your package.json:
// {
//   "name": "my-project",
//   "version": "1.0.0",
//   "devDependencies": {
//     "jest": "^29.0.0",
//     "jest-json-reporter": "^1.0.0"
//   },
//   "jest": {
//     "testResultsProcessor": "./node_modules/jest-json-reporter",
//     "testEnvironment": "node"
//   },
//   "jestJsonReporter": {
//     "outputFile": "jest-test-results.json"
//   }
// }

// __tests__/example.test.ts
// Create a simple test file, e.g., '__tests__/example.test.ts':
describe('Basic math operations', () => {
  test('adds 1 + 2 to equal 3', () => {
    expect(1 + 2).toBe(3);
  });

  test('multiplies 2 * 3 to equal 6', () => {
    expect(2 * 3).toBe(6);
  });
});

// Run Jest from your terminal
npx jest

// Verify the JSON output file
// cat jest-test-results.json

view raw JSON →