add input history tests

src/__tests__/webInputHistory.test.tsx

@@ -0,0 +1,115 @@
+import {expect} from '@jest/globals';
+import InputHistory from '../web/InputHistory';
+
+const testingHistory = [
+  {text: 'Hello world!', cursorPosition: 12},
+  {text: 'Hello *world*!', cursorPosition: 14},
+  {text: 'Hello _*world*_!', cursorPosition: 16},
+];
+const depth = testingHistory.length;
+
+test('add history action', () => {
+  const history = new InputHistory(depth);
+  testingHistory.forEach((item) => {
+    history.add(item.text, item.cursorPosition);
+  });
+
+  expect(history.history).toEqual(testingHistory);
+  expect(history.getCurrentItem()).toEqual(testingHistory[testingHistory.length - 1]);
+});
+
+test('history depth', () => {
+  const history = new InputHistory(depth);
+  const text = '> Hello _*world*_!';
+
+  history.setHistory(testingHistory);
+  history.add(text, text.length);
+
+  const newItem = {text, cursorPosition: text.length};
+  const currentHistory = [...testingHistory.slice(1), newItem];
+
+  expect(history.history).toEqual(currentHistory);
+  expect(history.getCurrentItem()).toEqual(newItem);
+});
+
+describe('debounce add history action', () => {
+  const text = 'Hello world!';
+  const newItem = {text, cursorPosition: text.length};
+  const text2 = 'Hello world 2!';
+  const newItem2 = {text: text2, cursorPosition: text2.length};
+
+  beforeEach(() => {
+    jest.useFakeTimers();
+  });
+
+  afterEach(() => {
+    jest.runOnlyPendingTimers();
+    jest.useRealTimers();
+  });
+
+  test('should debounce', () => {
+    const history = new InputHistory(depth, 300);
+    history.debouncedAdd(newItem.text, newItem.cursorPosition);
+    expect(history.history).toEqual([]);
+    jest.advanceTimersByTime(300);
+    expect(history.history).toEqual([newItem]);
+  });
+
+  test('should cancel previous invocation', () => {
+    const history = new InputHistory(depth, 300);
+    history.debouncedAdd(newItem.text, newItem.cursorPosition);
+    jest.advanceTimersByTime(100);
+    history.debouncedAdd(newItem2.text, newItem2.cursorPosition);
+    jest.advanceTimersByTime(300);
+    expect(history.history).toEqual([newItem2]);
+  });
+
+  test('undo before debounce invokes the function', () => {
+    const history = new InputHistory(depth, 300);
+    history.debouncedAdd(newItem.text, newItem.cursorPosition);
+    expect(history.undo()).toEqual(null);
+    jest.advanceTimersByTime(300);
+    expect(history.history).toEqual([]);
+  });
+
+  test('redo before debounce invokes the function', () => {
+    const history = new InputHistory(depth, 300);
+    history.debouncedAdd(newItem.text, newItem.cursorPosition);
+    expect(history.redo()).toEqual(null);
+    jest.advanceTimersByTime(300);
+    expect(history.history).toEqual([]);
+  });
+});
+
+test('undo history action', () => {
+  const history = new InputHistory(depth);
+  history.setHistory(testingHistory);
+
+  expect(history.undo()).toEqual(testingHistory[1]);
+
+  history.setHistoryIndex(0);
+  expect(history.undo()).toEqual(null);
+});
+
+test('redo history action', () => {
+  const history = new InputHistory(depth);
+  history.setHistory(testingHistory);
+  expect(history.redo()).toEqual(null);
+
+  history.setHistoryIndex(1);
+  expect(history.redo()).toEqual(testingHistory[2]);
+});
+
+test('clearing history after adding new text after undo', () => {
+  const history = new InputHistory(depth);
+  history.setHistory(testingHistory);
+  history.setHistoryIndex(0);
+
+  const text = '> Hello _*world*_!';
+  const newItem = {text, cursorPosition: text.length};
+
+  history.add(newItem.text, newItem.cursorPosition);
+
+  expect(history.history).toEqual([testingHistory[0], newItem]);
+  expect(history.getCurrentItem()).toEqual(newItem);
+});

src/web/InputHistory.ts

@@ -23,6 +23,24 @@ export default class InputHistory {
     this.debounceTime = debounceTime;
   }
 
+  getCurrentItem(): HistoryItem | null {
+    return this.history[this.historyIndex] || null;
+  }
+
+  setHistory(newHistory: HistoryItem[]): void {
+    this.history = newHistory.slice(newHistory.length - this.depth);
+    this.historyIndex = newHistory.length - 1;
+  }
+
+  setHistoryIndex(index: number): void {
+    this.historyIndex = index;
+  }
+
+  clear(): void {
+    this.history = [];
+    this.historyIndex = 0;
+  }
+
   debouncedAdd(text: string, cursorPosition: number): void {
     this.currentText = text;
 
@@ -65,7 +83,7 @@ export default class InputHistory {
       return this.history[this.history.length - 1] || null;
     }
 
-    if (this.history.length === 0) {
+    if (this.history.length === 0 || this.historyIndex - 1 < 0) {
       return null;
     }
 
@@ -76,7 +94,12 @@ export default class InputHistory {
   }
 
   redo(): HistoryItem | null {
-    if (this.history.length === 0 || (this.currentText !== null && this.timeout)) {
+    if (this.currentText !== null && this.timeout) {
+      clearTimeout(this.timeout);
+      return this.history[this.history.length - 1] || null;
+    }
+
+    if (this.history.length === 0 || this.historyIndex + 1 > this.history.length) {
       return null;
     }
 
@@ -85,6 +108,7 @@ export default class InputHistory {
     } else {
       return null;
     }
+
     return this.history[this.historyIndex] || null;
   }
 }