feat: add test for unmounting multiple inputs, closes #712

fix: change trottle to debounce

__tests__/Formsy.spec.tsx

@@ -770,7 +770,13 @@ describe('value === false', () => {
   });
 
   it('should be able to set a deep value with updateInputsWithValue', () => {
-    class TestForm extends React.Component<{}, { valueBar: number; valueFoo: { valueBar: number } }> {
+    class TestForm extends React.Component<
+      {},
+      {
+        valueBar: number;
+        valueFoo: { valueBar: number };
+      }
+    > {
       formRef = React.createRef<Formsy>();
 
       constructor(props) {
@@ -1061,7 +1067,12 @@ describe('form valid state', () => {
   it('should be false when validationErrors is not empty', () => {
     let isValid = true;
 
-    class TestForm extends React.Component<{}, { validationErrors: { [key: string]: ValidationError } }> {
+    class TestForm extends React.Component<
+      {},
+      {
+        validationErrors: { [key: string]: ValidationError };
+      }
+    > {
       constructor(props) {
         super(props);
         this.state = {
@@ -1102,7 +1113,12 @@ describe('form valid state', () => {
   it('should be true when validationErrors is not empty and preventExternalInvalidation is true', () => {
     let isValid = true;
 
-    class TestForm extends React.Component<{}, { validationErrors: { [key: string]: ValidationError } }> {
+    class TestForm extends React.Component<
+      {},
+      {
+        validationErrors: { [key: string]: ValidationError };
+      }
+    > {
       constructor(props) {
         super(props);
         this.state = {
@@ -1197,7 +1213,45 @@ describe('form valid state', () => {
 
     render(<TestForm />);
 
-    expect(validSpy).toHaveBeenCalledTimes(1 + 1); // one for form mount & 1 for all attachToForm calls
+    expect(validSpy).toHaveBeenCalledTimes(1);
+  });
+
+  it('should revalidate form once when unmounting multiple inputs', () => {
+    const Inputs = () => {
+      const [showInputs, setShowInputs] = useState(true);
+
+      return (
+        <>
+          <button type="button" onClick={() => setShowInputs(!showInputs)} data-testid="toggle-btn">
+            toggle inputs
+          </button>
+          {showInputs &&
+            Array.from({ length: 10 }, (_, index) => (
+              <TestInput key={index} name={`foo-${index}`} required={true} value={`${index}`} />
+            ))}
+        </>
+      );
+    };
+
+    const validSpy = jest.fn();
+
+    const TestForm = () => (
+      <Formsy onValid={validSpy}>
+        <Inputs />
+      </Formsy>
+    );
+
+    jest.useFakeTimers();
+    const screen = render(<TestForm />);
+    jest.runAllTimers();
+    const toggleBtn = screen.getByTestId('toggle-btn');
+
+    validSpy.mockClear();
+
+    fireEvent.click(toggleBtn);
+    jest.runAllTimers();
+
+    expect(validSpy).toHaveBeenCalledTimes(1);
   });
 });
 

src/Formsy.ts

@@ -12,7 +12,7 @@ import {
   IUpdateInputsWithValue,
   ValidationError,
 } from './interfaces';
-import { throttle, isObject, isString } from './utils';
+import { debounce, isObject, isString } from './utils';
 import * as utils from './utils';
 import validationRules from './validationRules';
 import { PassDownProps } from './withFormsy';
@@ -103,7 +103,7 @@ export class Formsy extends React.Component<FormsyProps, FormsyState> {
     formElement: 'form',
   };
 
-  private readonly throttledValidateForm: () => void;
+  private readonly debouncedValidateForm: () => void;
 
   public constructor(props: FormsyProps) {
     super(props);
@@ -122,7 +122,7 @@ export class Formsy extends React.Component<FormsyProps, FormsyState> {
     };
     this.inputs = [];
     this.emptyArray = [];
-    this.throttledValidateForm = throttle(this.validateForm, ONE_RENDER_FRAME);
+    this.debouncedValidateForm = debounce(this.validateForm, ONE_RENDER_FRAME);
   }
 
   public componentDidMount = () => {
@@ -336,20 +336,15 @@ export class Formsy extends React.Component<FormsyProps, FormsyState> {
       onChange(this.getModel(), this.isChanged());
     }
 
-    // Will be triggered immediately & every one frame rate
-    this.throttledValidateForm();
+    this.debouncedValidateForm();
   };
 
   // Method put on each input component to unregister
   // itself from the form
   public detachFromForm = <V>(component: InputComponent<V>) => {
-    const componentPos = this.inputs.indexOf(component);
+    this.inputs = this.inputs.filter((input) => input !== component);
 
-    if (componentPos !== -1) {
-      this.inputs = this.inputs.slice(0, componentPos).concat(this.inputs.slice(componentPos + 1));
-    }
-
-    this.throttledValidateForm();
+    this.debouncedValidateForm();
   };
 
   // Checks if the values have changed from their initial value
@@ -437,7 +432,7 @@ export class Formsy extends React.Component<FormsyProps, FormsyState> {
   // and check their state
   public validateForm = () => {
     // We need a callback as we are validating all inputs again. This will
-    // run when the last component has set its state
+    // run when the last input has set its state
     const onValidationComplete = () => {
       const allIsValid = this.inputs.every((component) => component.state.isValid);
 
@@ -449,24 +444,17 @@ export class Formsy extends React.Component<FormsyProps, FormsyState> {
       });
     };
 
-    // Run validation again in case affected by other inputs. The
-    // last component validated will run the onValidationComplete callback
-    this.inputs.forEach((component, index) => {
-      const validationState = this.runValidation(component);
-      const isFinalInput = index === this.inputs.length - 1;
-      const callback = isFinalInput ? onValidationComplete : null;
-      component.setState(validationState, callback);
-    });
-
-    // If there are no inputs, set state where form is ready to trigger
-    // change event. New inputs might be added later
-    if (!this.inputs.length) {
-      this.setState(
-        {
-          canChange: true,
-        },
-        onValidationComplete,
-      );
+    if (this.inputs.length === 0) {
+      onValidationComplete();
+    } else {
+      // Run validation again in case affected by other inputs. The
+      // last component validated will run the onValidationComplete callback
+      this.inputs.forEach((component, index) => {
+        const validationState = this.runValidation(component);
+        const isLastInput = index === this.inputs.length - 1;
+        const callback = isLastInput ? onValidationComplete : null;
+        component.setState(validationState, callback);
+      });
     }
   };
 

src/utils.ts

@@ -143,14 +143,12 @@ export function runRules<V>(
   return results;
 }
 
-export function throttle(callback, interval) {
-  let enableCall = true;
-
-  return function (...args) {
-    if (!enableCall) return;
-
-    enableCall = false;
-    callback.apply(this, args);
-    setTimeout(() => (enableCall = true), interval);
+export function debounce(callback, timeout: number) {
+  let timer;
+  return (...args) => {
+    clearTimeout(timer);
+    timer = setTimeout(() => {
+      callback.apply(this, args);
+    }, timeout);
   };
 }