Improve undo/redo for Title component

src/app/core/models/undoredo.model.ts

@@ -20,6 +20,21 @@ export class UndoRedo<T> {
     this.intervalTime = intervalTime;
   }
 
+  public static isUndo(event: KeyboardEvent) {
+    // prevents undo from firing when ctrl shift z is pressed
+    if (navigator.platform.indexOf('Mac') === 0) {
+      return event.metaKey && event.code === 'KeyZ' && !event.shiftKey;
+    }
+    return event.ctrlKey && event.code === 'KeyZ' && !event.shiftKey;
+  }
+
+  public static isRedo(event: KeyboardEvent) {
+    if (navigator.platform.indexOf('Mac') === 0) {
+      return event.metaKey && event.shiftKey && event.code === 'KeyZ';
+    }
+    return (event.ctrlKey && event.shiftKey && event.code === 'KeyZ') || (event.ctrlKey && event.code === 'KeyY');
+  }
+
   /**
    * Function to be called right before a change is made / stores the latest last state
    * preferably to be called with "beforeinput" event

src/app/phase-bug-reporting/new-issue/new-issue.component.css

@@ -3,7 +3,7 @@
   margin: 0 auto;
 }
 
-mat-form-field {
+app-title-editor {
   width: 100%;
 }
 

src/app/phase-bug-reporting/new-issue/new-issue.component.html

@@ -4,12 +4,12 @@ <h1 class="mat-display-1 title">New Issue</h1>
   <div class="form">
     <div class="row">
       <div class="column left">
-        <mat-form-field>
-          <input id="title" formControlName="title" matInput placeholder="Title" required maxlength="256" />
-          <mat-error *ngIf="title.errors && title.errors['required'] && (title.touched || title.dirty)"> Title required. </mat-error>
-          <mat-error *ngIf="title.errors && title.errors['maxlength']"> Title cannot exceed 256 characters. </mat-error>
-          <mat-hint *ngIf="title.value?.length >= 206"> {{ 256 - title.value?.length }} characters remaining. </mat-hint>
-        </mat-form-field>
+        <app-title-editor
+          [id]="'title'"
+          [titleField]="title"
+          [titleForm]="this.newIssueForm"
+        >
+        </app-title-editor>
 
         <div style="margin: 10px 0 10px 0">
           <app-comment-editor

src/app/phase-bug-reporting/new-issue/new-issue.component.ts

@@ -28,7 +28,7 @@ export class NewIssueComponent implements OnInit {
 
   ngOnInit() {
     this.newIssueForm = this.formBuilder.group({
-      title: ['', [Validators.required, Validators.maxLength(256)]],
+      title: [''],
       description: [''],
       severity: ['', Validators.required],
       type: ['', Validators.required]

src/app/shared/comment-editor/comment-editor.component.ts

@@ -92,11 +92,11 @@ export class CommentEditorComponent implements OnInit {
   }
 
   onKeyPress(event: KeyboardEvent) {
-    if (this.isUndo(event)) {
+    if (UndoRedo.isUndo(event)) {
       event.preventDefault();
       this.undo();
       return;
-    } else if (this.isRedo(event)) {
+    } else if (UndoRedo.isRedo(event)) {
       this.redo();
       event.preventDefault();
       return;
@@ -347,21 +347,6 @@ export class CommentEditorComponent implements OnInit {
     return event.ctrlKey;
   }
 
-  private isUndo(event: KeyboardEvent) {
-    // prevents undo from firing when ctrl shift z is pressed
-    if (navigator.platform.indexOf('Mac') === 0) {
-      return event.metaKey && event.code === 'KeyZ' && !event.shiftKey;
-    }
-    return event.ctrlKey && event.code === 'KeyZ' && !event.shiftKey;
-  }
-
-  private isRedo(event: KeyboardEvent) {
-    if (navigator.platform.indexOf('Mac') === 0) {
-      return event.metaKey && event.shiftKey && event.code === 'KeyZ';
-    }
-    return (event.ctrlKey && event.shiftKey && event.code === 'KeyZ') || (event.ctrlKey && event.code === 'KeyY');
-  }
-
   private insertOrRemoveCharsFromHighlightedText(char) {
     const selectionStart = this.commentTextArea.nativeElement.selectionStart;
     const selectionEnd = this.commentTextArea.nativeElement.selectionEnd;

src/app/shared/issue/issue-components.module.ts

@@ -10,13 +10,20 @@ import { DescriptionComponent } from './description/description.component';
 import { DuplicatedIssuesComponent } from './duplicatedIssues/duplicated-issues.component';
 import { DuplicateOfComponent } from './duplicateOf/duplicate-of.component';
 import { LabelComponent } from './label/label.component';
+import { TitleEditorComponent } from './title-editor/title-editor.component';
 import { TitleComponent } from './title/title.component';
 import { UnsureCheckboxComponent } from './unsure-checkbox/unsure-checkbox.component';
 
 @NgModule({
-  imports: [SharedModule, CommentEditorModule, MatProgressBarModule, NgxMatSelectSearchModule, MarkdownModule.forChild()],
+  imports: [
+    SharedModule,
+    CommentEditorModule,
+    MatProgressBarModule,
+    NgxMatSelectSearchModule,
+    MarkdownModule.forChild()],
   declarations: [
     TitleComponent,
+    TitleEditorComponent,
     DescriptionComponent,
     LabelComponent,
     AssigneeComponent,
@@ -27,6 +34,7 @@ import { UnsureCheckboxComponent } from './unsure-checkbox/unsure-checkbox.compo
   ],
   exports: [
     TitleComponent,
+    TitleEditorComponent,
     DescriptionComponent,
     LabelComponent,
     AssigneeComponent,

src/app/shared/issue/title-editor/title-editor.component.css

@@ -0,0 +1,3 @@
+mat-form-field {
+  width: 100%;
+}

src/app/shared/issue/title-editor/title-editor.component.html

@@ -0,0 +1,25 @@
+<form [formGroup]="titleForm">
+  <mat-form-field>
+    <input
+      (keydown)="onKeyPress($event)"
+      (beforeinput)="handleBeforeInputChange($event)"
+      (input)="handleInputChange($event)"
+      #titleInput 
+      id="{{ this.id }}" 
+      formControlName="{{ this.id }}" 
+      matInput
+      required
+      placeholder="{{ this.placeholderText }}"
+      maxlength="{{ this.maxLength }}"
+    />
+    <mat-error *ngIf="titleField.errors && titleField.errors['required'] && (titleField.touched || titleField.dirty)"> 
+      Title required.
+    </mat-error>
+    <mat-error *ngIf="titleField.errors && titleField.errors['maxlength']">
+      Title cannot exceed {{ maxLength }} characters.
+    </mat-error>
+    <mat-hint *ngIf="titleField.value?.length >= maxLength - 50">
+      {{ maxLength - titleField.value?.length }} characters remaining.
+    </mat-hint>
+  </mat-form-field>
+</form>

src/app/shared/issue/title-editor/title-editor.component.ts

@@ -0,0 +1,119 @@
+import { Component, ElementRef, Input, OnInit, ViewChild } from '@angular/core';
+import { AbstractControl, FormGroup, Validators } from '@angular/forms';
+import { UndoRedo } from '../../../core/models/undoredo.model';
+
+const ISSUE_BODY_SIZE_LIMIT = 256;
+
+type textEntry = {
+  text: string;
+  selectStart: number;
+  selectEnd: number;
+};
+
+@Component({
+  selector: 'app-title-editor',
+  templateUrl: './title-editor.component.html',
+  styleUrls: ['./title-editor.component.css']
+})
+export class TitleEditorComponent implements OnInit {
+
+  constructor() {}
+
+  @Input() titleField: AbstractControl; // Compulsory Input
+  @Input() titleForm: FormGroup; // Compulsory Input
+  @Input() id: string; // Compulsory Input
+
+  @Input() initialTitle?: string;
+  placeholderText = 'Title';
+
+  @ViewChild('titleInput', { static: true }) titleInput: ElementRef<HTMLInputElement>;
+
+  maxLength = ISSUE_BODY_SIZE_LIMIT;
+
+  history: UndoRedo<textEntry>;
+
+  ngOnInit() {
+    if (this.initialTitle !== undefined) {
+      this.titleField.setValue(this.initialTitle);
+    }
+
+    if (this.titleField === undefined || this.titleForm === undefined || this.id === undefined) {
+      throw new Error("Title Editor's compulsory properties are not defined.");
+    }
+
+    this.titleField.setValidators([Validators.required, Validators.maxLength(this.maxLength)]);
+    this.history = new UndoRedo<textEntry>(
+      75,
+      () => {
+        return {
+          text: this.titleInput.nativeElement.value,
+          selectStart: this.titleInput.nativeElement.selectionStart,
+          selectEnd: this.titleInput.nativeElement.selectionEnd
+        };
+      },
+      500
+    );
+  }
+
+  onKeyPress(event: KeyboardEvent) {
+    if (UndoRedo.isUndo(event)) {
+      event.preventDefault();
+      this.undo();
+      return;
+    } else if (UndoRedo.isRedo(event)) {
+      this.redo();
+      event.preventDefault();
+      return;
+    }
+  }
+
+  handleBeforeInputChange(event: InputEvent): void {
+    switch (event.inputType) {
+      case 'historyUndo':
+      case 'historyRedo':
+        // ignore these events that doesn't modify the text
+        event.preventDefault();
+        break;
+      case 'insertFromPaste':
+        this.history.forceSave(null, true, false);
+        break;
+
+      default:
+        this.history.updateBeforeChange();
+    }
+  }
+
+  handleInputChange(event: InputEvent): void {
+    switch (event.inputType) {
+      case 'historyUndo':
+      case 'historyRedo':
+        // ignore these events that doesn't modify the text
+        event.preventDefault();
+        break;
+      case 'insertFromPaste':
+        // paste events will be handled exclusively by handleBeforeInputChange
+        break;
+
+      default:
+        this.history.createDelayedSave();
+    }
+  }
+
+  private undo(): void {
+    const entry = this.history.undo();
+    if (entry === null) {
+      return;
+    }
+    this.titleField.setValue(entry.text);
+    this.titleInput.nativeElement.setSelectionRange(entry.selectStart, entry.selectEnd);
+  }
+
+  private redo(): void {
+    const entry = this.history.redo();
+    if (entry === null) {
+      return;
+    }
+    this.titleInput.nativeElement.value = entry.text;
+    this.titleInput.nativeElement.setSelectionRange(entry.selectStart, entry.selectEnd);
+  }
+}

src/app/shared/issue/title/title.component.css

@@ -13,11 +13,16 @@
 .title-button {
   display: flex;
   flex-direction: row;
+  justify-content: center;
   align-items: center;
   margin: 5px;
   float: right;
 }
 
+app-title-editor {
+  width: 80%;
+}
+
 :host ::ng-deep .mat-progress-spinner {
   color: rgba(0, 0, 0, 0.5);
   display: inline-block;

src/app/shared/issue/title/title.component.html

@@ -20,28 +20,30 @@ <h1 class="mat-display-1 title">
 
 <div *ngIf="isEditing">
   <form [formGroup]="issueTitleForm" #myForm="ngForm" (ngSubmit)="updateTitle(myForm)">
-    <mat-form-field style="width: 80%">
-      <input id="title" formControlName="title" matInput placeholder="Title" required maxlength="256" />
-      <mat-error *ngIf="issueTitleForm.get('title').hasError('required')"> Title is required. </mat-error>
-      <mat-error *ngIf="issueTitleForm.get('title').hasError('maxlength')"> Title cannot exceed 256 characters. </mat-error>
-      <mat-hint *ngIf="issueTitleForm.get('title').value?.length >= 206">
-        {{ 256 - issueTitleForm.get('title').value?.length }} characters remaining.
-      </mat-hint>
-    </mat-form-field>
-
-    <button type="submit" [disabled]="issueTitleForm.invalid || isSavePending" mat-stroked-button color="primary" class="title-button">
-      Save
-      <ng-container #loadingSpinnerContainer></ng-container>
-    </button>
-    <button
-      type="button"
-      [disabled]="isSavePending"
-      mat-stroked-button
-      color="warn"
-      class="title-button"
-      (click)="openCancelDialogIfModified()"
-    >
-      Cancel
-    </button>
+    <div class="row">
+      <app-title-editor
+        [id]="'title'"
+        [titleField]="this.issueTitleForm.get('title')"
+        [titleForm]="this.issueTitleForm"
+      >
+      </app-title-editor>
+
+      <div>
+        <button type="submit" [disabled]="issueTitleForm.invalid" mat-stroked-button color="primary" class="title-button">
+          Save
+          <ng-container #loadingSpinnerContainer></ng-container>
+        </button>
+        <button
+          type="button"
+          [disabled]="isSavePending"
+          mat-stroked-button
+          color="warn"
+          class="title-button"
+          (click)="openCancelDialogIfModified()"
+        >
+          Cancel
+        </button>
+      </div>
+    </div>
   </form>
 </div>

src/app/shared/issue/title/title.component.ts

@@ -47,7 +47,7 @@ export class TitleComponent implements OnInit {
 
   ngOnInit() {
     this.issueTitleForm = this.formBuilder.group({
-      title: new FormControl('', [Validators.required, Validators.maxLength(256)])
+      title: ['']
     });
     // Build the loading service spinner
     this.loadingService