avajs/ava · error · Error

nonSemVerExperiments.${key} from ${fileForErrorMessage} is n

Error message

nonSemVerExperiments.${key} from ${fileForErrorMessage} is not a supported experiment

What it means

Guard in loadConfig: a key inside the nonSemVerExperiments object is not in the EXPERIMENTS registry — an unknown or typo'd experiment name, or one removed in this AVA version. The input at fault is the offending nonSemVerExperiments.<key> entry.

Source

Thrown at lib/load-config.js:173

	const config = {
		...defaults, nonSemVerExperiments: {}, ...fileConf, ...packageConf, projectDir, configFile,
	};

	if (
		'filterNodeArgumentsForWorkerThreads' in config
		&& typeof config.filterNodeArgumentsForWorkerThreads !== 'function'
	) {
		throw new Error(`filterNodeArgumentsForWorkerThreads from ${fileForErrorMessage} must be a function`);
	}

	const {nonSemVerExperiments: experiments} = config;
	if (!isPlainObject(experiments)) {
		throw new Error(`nonSemVerExperiments from ${fileForErrorMessage} must be an object`);
	}

	for (const key of Object.keys(experiments)) {
		if (!EXPERIMENTS.has(key)) {
			throw new Error(`nonSemVerExperiments.${key} from ${fileForErrorMessage} is not a supported experiment`);
		}
	}

	return {config, unsupportedFiles};
}

View on GitHub (pinned to bbfd946322)

Solutions

  1. Check the AVA documentation for currently supported non-semantic-version experiment names
  2. Fix typos in the experiment key
  3. Remove stale experiment flags when upgrading AVA
Defensive patterns

Strategy: validation

When it happens

Trigger: Thrown at lib/load-config.js:173 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of avajs/ava@bbfd946322 (2026-09-02). Data as JSON: /api/errors/f7a5aaef0421dae1. Report an issue: GitHub.