appsmithorg/appsmith · error · ActionValidationError

showAlert expected STRING for 'message' argument but receive

Error message

showAlert expected STRING for 'message' argument but received ${received}

What it means

ActionValidationError thrown by showAlertSaga when payload.message is not a string. showAlert builds a toast, and toasts require a string body, so the saga validates the argument type synchronously before calling showToast. The error message is rendered via the TRIGGER_ACTION_VALIDATION_ERROR template.

Source

Thrown at app/client/src/sagas/ActionExecution/ShowAlertActionSaga.ts:18

import AppsmithConsole from "utils/AppsmithConsole";
import { ActionValidationError } from "sagas/ActionExecution/errorUtils";
import { getType, Types } from "utils/TypeHelpers";
import type { ToastKind } from "@appsmith/ads";
import type { TShowAlertDescription } from "workers/Evaluation/fns/showAlert";
import { call } from "redux-saga/effects";
import showToast from "sagas/ToastSagas";
import { uniqueId } from "lodash";
import type { SourceEntity } from "entities/AppsmithConsole";

export default function* showAlertSaga(
  action: TShowAlertDescription,
  source?: SourceEntity,
) {
  const { payload } = action;

  if (typeof payload.message !== "string") {
    throw new ActionValidationError(
      "SHOW_ALERT",
      "message",
      Types.STRING,
      getType(payload.message),
    );
  }

  // This is the toast that is rendered which is user generated by using `showAlert` platform function. This is forceDisplayed no matter the conditions.
  yield call(
    showToast,
    payload.message,
    {
      kind: payload.style as ToastKind,
      toastId: uniqueId("ToastId"),
    },
    { forceDisplay: true },
  );
  AppsmithConsole.info({

View on GitHub (pinned to 8cd9021c24)

Solutions

1. Pass a string literal: showAlert('Saved', 'success').
2. Drill into the specific string field: showAlert(getApi.data.message).
3. Coerce with String(...) or fall back to a default when the bound value may be missing.

Example fix

// before
showAlert(getApi.data); // object
// after
showAlert(getApi.data.message ?? 'No message');

const msg = typeof payload === 'string' ? payload : String(payload ?? '');
if (!msg) { showAlert('Message is required', 'error'); return; }
showAlert(msg, 'success');

function isAlertMessage(v: unknown): v is string {
  return typeof v === 'string' && v.length > 0;
}

try {
  showAlert(message);
} catch (e) {
  if (e instanceof ActionValidationError) console.warn(e.message);
}

When it happens

Trigger: Calling showAlert() with a number, object, array, undefined, or null message; binding message to a query response that resolves to an object (e.g. an entire API response) rather than a string field.

Common situations: Binding {{ getApi.data }} (object) instead of {{ getApi.data.message }}; passing a raw JS object literal; chaining showAlert after an action that returned undefined.

Related errors

• resetWidget expected STRING for 'widgetName' argument but re
• The ${path} path must start with 'https://'.
• error
• Please enter a target origin URL.
• onThemeChange expects a function as parameter

AI-assisted analysis of appsmithorg/appsmith@8cd9021c24 (2026-08-12). Data as JSON: /api/errors/9bc0724d835a622f. Report an issue: GitHub.