mocha-ssst

A Mocha reporter that hides what is written to console during tests, unless a test fails.

Installation

npm install -D @ppwcode/mocha-ssst

In package.json:

{
  "...": "…",
  "mocha": {
    "...": "…",
    "reporter": ["@ppwcode/mocha-ssst"]
  },
  "....": "…"
}

Why

There are ample reasons to use console.log(…) in production code, e.g., to easily use the structured logging provided by AWS Lambdas. And even if you don’t do that, some of your dependencies might.

Furthermore, we like to console.log(…) progress, results, and intermediate results in our Mocha test code. It gives a warm confidence while developing, e.g., using WebStorm. The JetBrains reporter shows these logs clean and isolated. And these logs help enormously when something goes wrong later, in CI. This is not meant to replace automated validation of your results.

We like the Mocha Spec reporter a lot. It gives us a clear view of what is happening and how the tests progress. The other reporters, to us, are less informative.

But if you combine these 2, the output of production code and test code console.log(…) calls is immediate, and messes up the report.

What

This reporter alleviates that. It behaves like the Mocha Spec reporter, but console.log(…) outputs are buffered.

Logs are only shown when the test fails or when the DEBUG environment variable is set to a non-empty value, and are shown below the test title.

DEBUG=true npm run test

Omit DEBUG (or leave it unset) to suppress buffered output. Any non-empty value enables it — including DEBUG=false — so unset DEBUG is the reliable way to turn it off.

Test errors are presented readably, and it doesn’t crash when test errors contain circular data structures.

ESM

This package is still CommonJS, because

Custom reporters and custom interfaces can only be CommonJS files

See Mocha, “Node.JS native ESM support”; “Current Limitations”.

Where

The npm package is at https://www.npmjs.com/package/@ppwcode/mocha-ssst.

The code is maintained in a Bitbucket repository.

Bug reports and other feedback should be directed at the repository’s issue management system at Bitbucket.

License

MIT

AI Agents

This repository contains special instructions for AI agents in AGENTS.md.

Fork

This started out as a fork of Wizcorp/mocha-reporter.

Wizcorp/mocha-reporter is unmaintained. The last commit is d.d. 2017-12-13. That version contains an annoying bug that results in false positive tests in cases where the error contains circular data structures.

After some years without a response, and since this is still our favorite reporter, this fork was created to fix the bug ourselves. The code has changed much. It is cleaned, modernized, and now the reporter has tests with 100% coverage.

Issues

• See Known vulnerabilities.
• See Known code issues and edge cases.
• Upgrading eslint to v10 is blocked by [email protected]. See neostandard #350.
• This will not work under Node 26, as, for the time being, mocha does not work on Node 26. See Node 26, yargs 17, Mocha, and c8.