grafana/k6 · error

invalid output encoding: %s

Error message

invalid output encoding: %s

What it means

Raised in Hasher.Digest's output-encoding switch: the computed sum is ready, but the requested outputEncoding ('%s') matches none of base64, base64url, base64rawurl, hex, or binary. This is a pure argument-validation guard on the encoding name — the hash itself succeeded and nothing is wrong with the input data or algorithm.

Source

Thrown at internal/js/modules/k6/crypto/crypto.go:259

	switch outputEncoding {
	case "base64":
		return base64.StdEncoding.EncodeToString(sum), nil

	case "base64url":
		return base64.URLEncoding.EncodeToString(sum), nil

	case "base64rawurl":
		return base64.URLEncoding.WithPadding(base64.NoPadding).EncodeToString(sum), nil

	case "hex":
		return hex.EncodeToString(sum), nil

	case "binary":
		ab := hasher.runtime.NewArrayBuffer(sum)
		return &ab, nil

	default:
		return nil, fmt.Errorf("invalid output encoding: %s", outputEncoding)
	}
}

View on GitHub (pinned to 01ffac6f24)

Solutions

  1. Use one of: base64, base64url, base64rawurl, hex, or binary
  2. Check spelling and case — the encoding name is matched exactly
  3. Omit the encoding argument if the default output is acceptable
Defensive patterns

Strategy: validation

When it happens

Trigger: Thrown at internal/js/modules/k6/crypto/crypto.go:259 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of grafana/k6@01ffac6f24 (2026-08-18). Data as JSON: /api/errors/3f24b6d9d5d8c864. Report an issue: GitHub.