Adds JavaScript to prevent multiple form submissions (#345)

- Disables the submit button on forms after click

[#185364171]

src/main/resources/META-INF/resources/webjars/form-flow/0.0.1/js/formFlowDisableMultipleFormSubmit.js

@@ -0,0 +1,12 @@
+document.addEventListener("DOMContentLoaded", function () {
+  const formSubmitButton = document.getElementById("form-submit-button");
+  if (formSubmitButton) {
+    const form = formSubmitButton.form;
+    if (form) {
+      form.addEventListener("submit", function () {
+        formSubmitButton.classList.add("button--disabled");
+        formSubmitButton.disabled = true;
+      });
+    }
+  }
+});

src/main/resources/templates/fragments/libraryHead.html

@@ -17,5 +17,6 @@
   <script src="/webjars/form-flow/0.0.1/js/honeycrisp.min.js"></script>
   <script src="/webjars/form-flow/0.0.1/js/formFlowDropZone.js"></script>
   <script src="/webjars/form-flow/0.0.1/js/formFlowLanguageSelector.js"></script>
+  <script src="/webjars/form-flow/0.0.1/js/formFlowDisableMultipleFormSubmit.js"></script>
 </th:block>
 </html>

src/test/java/formflow/library/client/DisableMultipleFormSubmitTest.java

@@ -0,0 +1,40 @@
+package formflow.library.client;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import static org.springframework.boot.test.context.SpringBootTest.WebEnvironment.RANDOM_PORT;
+
+import formflow.library.utilities.AbstractBasePageTest;
+import java.io.IOException;
+import java.time.Duration;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.openqa.selenium.By;
+import org.openqa.selenium.WebElement;
+
+import org.openqa.selenium.support.ui.ExpectedConditions;
+import org.openqa.selenium.support.ui.WebDriverWait;
+import org.springframework.boot.test.context.SpringBootTest;
+
+@SpringBootTest(properties = {"form-flow.path=flows-config/test-flow.yaml"}, webEnvironment = RANDOM_PORT)
+public class DisableMultipleFormSubmitTest extends AbstractBasePageTest {
+
+  @Override
+  @BeforeEach
+  public void setUp() throws IOException {
+    startingPage = "flow/testFlow/pageWithDefaultSubmitButton";
+    super.setUp();
+  }
+
+  @Test
+  void shouldNotSubmitFormMultipleTimes() {
+    WebElement formSubmitButton = testPage.findElementById("form-submit-button");
+    WebElement form = driver.findElement(By.tagName("form"));
+    driver.executeScript("arguments[0].addEventListener('submit', function(event) { event.preventDefault(); });", form);
+    formSubmitButton.click();
+    WebDriverWait wait = new WebDriverWait(driver, Duration.ofSeconds(5)); // wait up to 5 seconds
+    wait.until(ExpectedConditions.attributeToBe(formSubmitButton, "disabled", "true"));
+    assertThat(formSubmitButton.isEnabled()).isFalse();
+  }
+}