vitest-dev/vitest · error · PrettyFormatPluginError

error.message

Error message

error.message

What it means

A pretty-format plugin's serialize or print method threw an error during formatting; the catch wraps it into a PrettyFormatPluginError using error.message. This is a re-thrown plugin failure, not a pretty-format bug — the underlying message comes from inside the plugin that was selected to format the value.

try {
  format(value, { plugins })
} catch (e) {
  if (e instanceof PrettyFormatPluginError) {
    // inspect original plugin error via e.stack; disable/fallback plugin
    format(value, { plugins: plugins.filter(p => p !== suspect) })
  } else throw e
}

When it happens

Trigger: Any registered pretty-format plugin throwing while serializing a value (e.g. React/DOM/Immutable plugin encountering an unexpected shape, a plugin accessing a property that does not exist, circular refs mishandled).

Common situations: Custom plugin that throws on edge-case values; a third-party plugin incompatible with the value type; pretty-format invoked on an object whose getter throws; version skew between plugin and pretty-format.

Related errors

• Asymmetric matcher does not implement toAsymmetricMatcher()
• pretty-format: Plugin must return type "string" but instead…
• Cannot provide " " because it's not serializable.
• Cannot set serialized manual mock. Define a factory…
• Expected DOM element to be an instance of Element, received

AI-assisted analysis of vitest-dev/vitest@1fa9837ec2 (2026-08-11). Data as JSON: /api/errors/ba12c90670e0dc47. Report an issue: GitHub.

Appendix: source

Thrown at packages/pretty-format/src/index.ts:355

          val,
          valChild => printer(valChild, config, indentation, depth, refs),
          (str) => {
            const indentationNext = indentation + config.indent
            return (
              indentationNext
              + str.replaceAll(NEWLINE_REGEXP, `\n${indentationNext}`)
            )
          },
          {
            edgeSpacing: config.spacingOuter,
            min: config.min,
            spacing: config.spacingInner,
          },
          config.colors,
        )
  }
  catch (error: any) {
    throw new PrettyFormatPluginError(error.message, error.stack)
  }
  if (typeof printed !== 'string') {
    throw new TypeError(
      `pretty-format: Plugin must return type "string" but instead returned "${typeof printed}".`,
    )
  }
  return printed
}

function findPlugin(plugins: Plugins, val: unknown) {
  for (const plugin of plugins) {
    try {
      if (plugin.test(val)) {
        return plugin
      }
    }
    catch (error: any) {
      throw new PrettyFormatPluginError(error.message, error.stack)

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