undo-state.component: add limit support in insert()

Author: Garefild

projects/angular-redux2/undo/src/components/undo-state.component.spec.ts

@@ -33,6 +33,90 @@ describe('NgUndoStateActions', () => {
 
             expect(nextState).toBe(currentState); // Ensure the current state is returned
         });
+
+        test('should return the currentState if snapshot is undefined', () => {
+            const key = 'test';
+            const settings = {
+                path: [],
+                filter: () => true,
+                limit: 5
+            };
+
+            const currentState = { [HISTORY_STATE_KEY]: { [key]: { past: [] } } };
+            const snapshot = undefined;
+            const actions = new NgUndoStateActions(key, settings);
+            const result = actions.insert(currentState, snapshot);
+
+
+            expect(result).toBe(currentState);
+        });
+
+        test('should return the currentState if the filter function returns false', () => {
+            const key = 'test';
+            const settings = {
+                path: [],
+                filter: () => false,
+                limit: 5
+            };
+            const currentState = { [HISTORY_STATE_KEY]: { [key]: { past: [] } } };
+            const snapshot = 'snapshot';
+            const actions = new NgUndoStateActions(key, settings);
+            const result = actions.insert(currentState, snapshot);
+
+            expect(result).toBe(currentState);
+        });
+
+        test('should insert the snapshot into the past array and update the state', () => {
+            const key = 'test';
+            const settings = {
+                path: [],
+                filter: () => true,
+                limit: 5
+            };
+            const currentState = { [HISTORY_STATE_KEY]: { [key]: { past: [ 'past1', 'past2' ] } } };
+            const snapshot = 'snapshot';
+            const expectedState = {
+                [HISTORY_STATE_KEY]: {
+                    [key]: {
+                        past: [ 'past1', 'past2', 'snapshot' ],
+                        future: []
+                    }
+                }
+            };
+
+            const actions = new NgUndoStateActions(key, settings);
+            const result = actions.insert(currentState, snapshot);
+
+            expect(result).toEqual(expectedState);
+        });
+
+        test('should remove the oldest past snapshot if the past array exceeds the limit', () => {
+            const key = 'test';
+            const settings = {
+                path: [],
+                filter: () => true,
+                limit: 2
+            };
+            const currentState = {
+                [HISTORY_STATE_KEY]: {
+                    [key]: { past: [ 'past1', 'past2', 'past3' ] }
+                }
+            };
+            const snapshot = 'snapshot';
+            const expectedState = {
+                [HISTORY_STATE_KEY]: {
+                    [key]: {
+                        past: [ 'past2', 'past3', 'snapshot' ],
+                        future: []
+                    }
+                }
+            };
+
+            const actions = new NgUndoStateActions(key, settings);
+            const result = actions.insert(currentState, snapshot);
+
+            expect(result).toEqual(expectedState);
+        });
     });
 
     describe('undo', () => {

projects/angular-redux2/undo/src/components/undo-state.component.ts

@@ -8,7 +8,13 @@ import { get, set } from '@angular-redux2/store';
  * angular-redux2/undo
  */
 
-import { HISTORY_STATE_KEY, Settings } from '../interfaces/undo.interface';
+import { HISTORY_STATE_KEY } from '../interfaces/undo.interface';
+
+/**
+ * angular-redux2/undo types
+ */
+
+import type { Settings } from '../interfaces/undo.interface';
 
 /**
  * Represents the actions for managing undo state.
@@ -76,9 +82,12 @@ export class NgUndoStateActions {
         }
 
         const { state, undoState } = this.getStates(currentState);
-
         undoState.future = [];
 
+        if (undoState.past.length >= this.settings.limit) {
+            undoState.past = undoState.past.slice(1);
+        }
+
         return set(state, [ HISTORY_STATE_KEY, this.key, 'past' ], [
             ...undoState.past,
             snapshot
@@ -184,9 +193,8 @@ export class NgUndoStateActions {
         const snapshot = get(state, this.path);
         const activeSnapshot = undoState.future[index];
         const future = undoState.future.slice(index + 1);
-        const past = undoState.past.concat([ snapshot ], undoState.future.slice(0, index));
 
-        undoState.past = past;
+        undoState.past = undoState.past.concat([ snapshot ], undoState.future.slice(0, index));
         undoState.future = future;
 
         return set(state, this.path, activeSnapshot);