evanw/esbuild · error · Error

Missing "kind" in () call

Error message

Missing "kind" in ${callName}() call

What it means

The options object passed to formatMessages() must include `kind` set to 'error' or 'warning' so esbuild knows how to format the messages. At lib/shared/common.ts:798 the call throws if `kind` is undefined; a further check at line 799 rejects any other string value.

Solutions

1. Add `kind: 'error'` or `kind: 'warning'` to the options object.
2. Derive kind from the source: use 'error' for result.errors and 'warning' for result.warnings.

Example fix

// before
const out = await esbuild.formatMessages(result.errors, { color: true })

// after
const out = await esbuild.formatMessages(result.errors, { kind: 'error', color: true })

function safeFormatMessages(msgs, opts) {
  const kind = opts?.kind === 'error' || opts?.kind === 'warning'
    ? opts.kind
    : undefined
  if (!kind) throw new Error('formatMessages requires options.kind = "error" | "warning"')
  return esbuild.formatMessages(msgs, { ...opts, kind })
}
await safeFormatMessages(result.errors, { color: true })

function isFormatKind(v): v is 'error' | 'warning' {
  return v === 'error' || v === 'warning'
}

When it happens

Trigger: Calling `formatMessages(msgs, { color: true })`, `formatMessages(msgs, { terminalWidth: 80 })`, or any options object omitting `kind`.

Common situations: Passing only cosmetic options (color/terminalWidth) and forgetting kind; copy-pasting a partial options object.

Related errors

• Missing second argument in
• The input to "transform" must be a string or a Uint8Array
• Duplicated test name
• Expected onEnd() callback in plugin
• Expected onLoad() callback in plugin

AI-assisted analysis of evanw/esbuild@f6058f8364 (2026-08-09). Data as JSON: /api/errors/536769ac201eaf49. Report an issue: GitHub.

Appendix: source

Thrown at lib/shared/common.ts:798

        })
      }
    }
    if ((typeof input === 'string' || input instanceof Uint8Array) && input.length > 1024 * 1024) {
      let next = start
      start = () => fs.writeFile(input, next)
    }
    start(null)
  }

  let formatMessages: StreamService['formatMessages'] = ({ callName, refs, messages, options, callback }) => {
    if (!options) throw new Error(`Missing second argument in ${callName}() call`)
    let keys: OptionKeys = {}
    let kind = getFlag(options, keys, 'kind', mustBeString)
    let color = getFlag(options, keys, 'color', mustBeBoolean)
    let terminalWidth = getFlag(options, keys, 'terminalWidth', mustBeInteger)
    let logStyle = getFlag(options, keys, 'logStyle', mustBeString)
    checkForInvalidFlags(options, keys, `in ${callName}() call`)
    if (kind === void 0) throw new Error(`Missing "kind" in ${callName}() call`)
    if (kind !== 'error' && kind !== 'warning') throw new Error(`Expected "kind" to be "error" or "warning" in ${callName}() call`)
    let request: protocol.FormatMsgsRequest = {
      command: 'format-msgs',
      messages: sanitizeMessages(messages, 'messages', null, '', terminalWidth),
      isWarning: kind === 'warning',
    }
    if (color !== void 0) request.color = color
    if (terminalWidth !== void 0) request.terminalWidth = terminalWidth
    if (logStyle !== void 0) request.logStyle = logStyle
    sendRequest<protocol.FormatMsgsRequest, protocol.FormatMsgsResponse>(refs, request, (error, response) => {
      if (error) return callback(new Error(error), null)
      callback(null, response!.messages)
    })
  }

  let analyzeMetafile: StreamService['analyzeMetafile'] = ({ callName, refs, metafile, options, callback }) => {
    if (options === void 0) options = {}
    let keys: OptionKeys = {}

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