fix: trigger onChange in React (#626)

package.json

@@ -42,12 +42,16 @@
   "devDependencies": {
     "@testing-library/dom": "^7.28.1",
     "@testing-library/jest-dom": "^5.11.6",
+    "@testing-library/react": "^11.2.5",
     "@types/estree": "0.0.45",
     "@types/jest-in-case": "^1.0.3",
+    "@types/react": "^17.0.3",
     "is-ci": "^2.0.0",
     "jest-in-case": "^1.0.2",
     "jest-serializer-ansi": "^1.0.3",
     "kcd-scripts": "^7.5.1",
+    "react": "^17.0.2",
+    "react-dom": "^17.0.2",
     "typescript": "^4.1.2"
   },
   "peerDependencies": {

src/__tests__/react/tsconfig.json

@@ -0,0 +1,6 @@
+{
+  "extends": "../../../tsconfig.json",
+  "compilerOptions": {
+    "jsx": "react"
+  }
+}

src/__tests__/react/type.tsx

@@ -0,0 +1,15 @@
+import React from 'react'
+import {render, screen} from '@testing-library/react'
+import userEvent from 'index'
+
+test('trigger onChange SyntheticEvent on input', () => {
+  const inputHandler = jest.fn()
+  const changeHandler = jest.fn()
+
+  render(<input onInput={inputHandler} onChange={changeHandler} />)
+
+  userEvent.type(screen.getByRole('textbox'), 'abcdef')
+
+  expect(inputHandler).toHaveBeenCalledTimes(6)
+  expect(changeHandler).toHaveBeenCalledTimes(6)
+})

src/keyboard/shared/fireInputEvent.ts

@@ -23,9 +23,11 @@ export function fireInputEvent(
 ) {
   // apply the changes before firing the input event, so that input handlers can access the altered dom and selection
   if (isContentEditable(element)) {
-    element.textContent = newValue
-  } else /* istanbul ignore else */ if (isElementType(element, ['input', 'textarea'])) {
-    element.value = newValue
+    applyNative(element, 'textContent', newValue)
+  } /* istanbul ignore else */ else if (
+    isElementType(element, ['input', 'textarea'])
+  ) {
+    applyNative(element, 'value', newValue)
   } else {
     // TODO: properly type guard
     throw new Error('Invalid Element')
@@ -48,7 +50,7 @@ function setSelectionRangeAfterInput(
 
 function setSelectionRangeAfterInputHandler(
   element: Element,
-  newValue: string
+  newValue: string,
 ) {
   // if we *can* change the selection start, then we will if the new value
   // is the same as the current value (so it wasn't programatically changed
@@ -60,11 +62,41 @@ function setSelectionRangeAfterInputHandler(
 
   // don't apply this workaround on elements that don't necessarily report the visible value - e.g. number
   // TODO: this could probably be only applied when there is keyboardState.carryValue
-  const expectedValue = value === newValue || (value === '' && hasUnreliableEmptyValue(element))
-  if(!expectedValue) {
+  const expectedValue =
+    value === newValue || (value === '' && hasUnreliableEmptyValue(element))
+  if (!expectedValue) {
     // If the currentValue is different than the expected newValue and we *can*
     // change the selection range, than we should set it to the length of the
     // currentValue to ensure that the browser behavior is mimicked.
     setSelectionRange(element, value.length, value.length)
   }
 }
+
+/**
+ * React tracks the changes on element properties.
+ * This workaround tries to alter the DOM element without React noticing,
+ * so that it later picks up the change.
+ *
+ * @see https://github.com/facebook/react/blob/148f8e497c7d37a3c7ab99f01dec2692427272b1/packages/react-dom/src/client/inputValueTracking.js#L51-L104
+ */
+function applyNative<T extends Element, P extends keyof T>(
+  element: T,
+  propName: P,
+  propValue: T[P],
+) {
+  const descriptor = Object.getOwnPropertyDescriptor(element, propName)
+  const nativeDescriptor = Object.getOwnPropertyDescriptor(
+    element.constructor.prototype,
+    propName,
+  )
+
+  if (descriptor && nativeDescriptor) {
+    Object.defineProperty(element, propName, nativeDescriptor)
+  }
+
+  element[propName] = propValue
+
+  if (descriptor) {
+    Object.defineProperty(element, propName, descriptor)
+  }
+}

tsconfig.json

@@ -1,7 +1,8 @@
 {
   "extends": "./node_modules/kcd-scripts/shared-tsconfig.json",
   "compilerOptions": {
-    "allowJs": true
+    "allowJs": true,
+    "esModuleInterop": true
   },
   "include": ["./src", "./typings"]
 }