Add lint rule to ensure _on prefix is only for event emitters

.eslintrc.json

@@ -101,6 +101,14 @@
         "regex": "^on[A-Z].+",
         "match": false
       } },
+      { "selector": "method", "modifiers": ["private"], "format": ["camelCase"], "leadingUnderscore": "require", "custom": {
+        "regex": "^on[A-Z].+",
+        "match": false
+      } },
+      { "selector": "method", "modifiers": ["protected"], "format": ["camelCase"], "leadingUnderscore": "require", "custom": {
+        "regex": "^on[A-Z].+",
+        "match": false
+      } },
       // typeLike
       { "selector": "typeLike", "format": ["PascalCase"] },
       { "selector": "interface", "format": ["PascalCase"], "prefix": ["I"] }

addons/xterm-addon-canvas/src/LinkRenderLayer.ts

@@ -28,8 +28,8 @@ export class LinkRenderLayer extends BaseRenderLayer {
   ) {
     super(terminal, container, 'link', zIndex, true, colors, bufferService, optionsService, decorationService, coreBrowserService);
 
-    this.register(linkifier2.onShowLinkUnderline(e => this._onShowLinkUnderline(e)));
-    this.register(linkifier2.onHideLinkUnderline(e => this._onHideLinkUnderline(e)));
+    this.register(linkifier2.onShowLinkUnderline(e => this._handleShowLinkUnderline(e)));
+    this.register(linkifier2.onHideLinkUnderline(e => this._handleHideLinkUnderline(e)));
   }
 
   public resize(dim: IRenderDimensions): void {
@@ -54,7 +54,7 @@ export class LinkRenderLayer extends BaseRenderLayer {
     }
   }
 
-  private _onShowLinkUnderline(e: ILinkifierEvent): void {
+  private _handleShowLinkUnderline(e: ILinkifierEvent): void {
     if (e.fg === INVERTED_DEFAULT_COLOR) {
       this._ctx.fillStyle = this._colors.background.css;
     } else if (e.fg && is256Color(e.fg)) {
@@ -78,7 +78,7 @@ export class LinkRenderLayer extends BaseRenderLayer {
     this._state = e;
   }
 
-  private _onHideLinkUnderline(e: ILinkifierEvent): void {
+  private _handleHideLinkUnderline(e: ILinkifierEvent): void {
     this._clearCurrentLink();
   }
 }

addons/xterm-addon-webgl/src/renderLayer/LinkRenderLayer.ts

@@ -24,8 +24,8 @@ export class LinkRenderLayer extends BaseRenderLayer {
   ) {
     super(container, 'link', zIndex, true, colors, coreBrowserService);
 
-    this.register(terminal.linkifier2.onShowLinkUnderline(e => this._onShowLinkUnderline(e)));
-    this.register(terminal.linkifier2.onHideLinkUnderline(e => this._onHideLinkUnderline(e)));
+    this.register(terminal.linkifier2.onShowLinkUnderline(e => this._handleShowLinkUnderline(e)));
+    this.register(terminal.linkifier2.onHideLinkUnderline(e => this._handleHideLinkUnderline(e)));
   }
 
   public resize(terminal: Terminal, dim: IRenderDimensions): void {
@@ -50,7 +50,7 @@ export class LinkRenderLayer extends BaseRenderLayer {
     }
   }
 
-  private _onShowLinkUnderline(e: ILinkifierEvent): void {
+  private _handleShowLinkUnderline(e: ILinkifierEvent): void {
     if (e.fg === INVERTED_DEFAULT_COLOR) {
       this._ctx.fillStyle = this._colors.background.css;
     } else if (e.fg !== undefined && is256Color(e.fg)) {
@@ -74,7 +74,7 @@ export class LinkRenderLayer extends BaseRenderLayer {
     this._state = e;
   }
 
-  private _onHideLinkUnderline(e: ILinkifierEvent): void {
+  private _handleHideLinkUnderline(e: ILinkifierEvent): void {
     this._clearCurrentLink();
   }
 }

src/browser/AccessibilityManager.ts

@@ -65,8 +65,8 @@ export class AccessibilityManager extends Disposable {
       this._rowContainer.appendChild(this._rowElements[i]);
     }
 
-    this._topBoundaryFocusListener = e => this._onBoundaryFocus(e, BoundaryPosition.TOP);
-    this._bottomBoundaryFocusListener = e => this._onBoundaryFocus(e, BoundaryPosition.BOTTOM);
+    this._topBoundaryFocusListener = e => this._handleBoundaryFocus(e, BoundaryPosition.TOP);
+    this._bottomBoundaryFocusListener = e => this._handleBoundaryFocus(e, BoundaryPosition.BOTTOM);
     this._rowElements[0].addEventListener('focus', this._topBoundaryFocusListener);
     this._rowElements[this._rowElements.length - 1].addEventListener('focus', this._bottomBoundaryFocusListener);
 
@@ -87,14 +87,14 @@ export class AccessibilityManager extends Disposable {
     this._terminal.element.insertAdjacentElement('afterbegin', this._accessibilityTreeRoot);
 
     this.register(this._renderRowsDebouncer);
-    this.register(this._terminal.onResize(e => this._onResize(e.rows)));
+    this.register(this._terminal.onResize(e => this._handleResize(e.rows)));
     this.register(this._terminal.onRender(e => this._refreshRows(e.start, e.end)));
     this.register(this._terminal.onScroll(() => this._refreshRows()));
     // Line feed is an issue as the prompt won't be read out after a command is run
-    this.register(this._terminal.onA11yChar(char => this._onChar(char)));
-    this.register(this._terminal.onLineFeed(() => this._onChar('\n')));
-    this.register(this._terminal.onA11yTab(spaceCount => this._onTab(spaceCount)));
-    this.register(this._terminal.onKey(e => this._onKey(e.key)));
+    this.register(this._terminal.onA11yChar(char => this._handleChar(char)));
+    this.register(this._terminal.onLineFeed(() => this._handleChar('\n')));
+    this.register(this._terminal.onA11yTab(spaceCount => this._handleTab(spaceCount)));
+    this.register(this._terminal.onKey(e => this._handleKey(e.key)));
     this.register(this._terminal.onBlur(() => this._clearLiveRegion()));
     this.register(this._renderService.onDimensionsChange(() => this._refreshRowsDimensions()));
 
@@ -110,7 +110,7 @@ export class AccessibilityManager extends Disposable {
     }));
   }
 
-  private _onBoundaryFocus(e: FocusEvent, position: BoundaryPosition): void {
+  private _handleBoundaryFocus(e: FocusEvent, position: BoundaryPosition): void {
     const boundaryElement = e.target as HTMLElement;
     const beforeBoundaryElement = this._rowElements[position === BoundaryPosition.TOP ? 1 : this._rowElements.length - 2];
 
@@ -170,7 +170,7 @@ export class AccessibilityManager extends Disposable {
     e.stopImmediatePropagation();
   }
 
-  private _onResize(rows: number): void {
+  private _handleResize(rows: number): void {
     // Remove bottom boundary listener
     this._rowElements[this._rowElements.length - 1].removeEventListener('focus', this._bottomBoundaryFocusListener);
 
@@ -198,13 +198,13 @@ export class AccessibilityManager extends Disposable {
     return element;
   }
 
-  private _onTab(spaceCount: number): void {
+  private _handleTab(spaceCount: number): void {
     for (let i = 0; i < spaceCount; i++) {
-      this._onChar(' ');
+      this._handleChar(' ');
     }
   }
 
-  private _onChar(char: string): void {
+  private _handleChar(char: string): void {
     if (this._liveRegionLineCount < MAX_ROWS_TO_READ + 1) {
       if (this._charsToConsume.length > 0) {
         // Have the screen reader ignore the char if it was just input
@@ -244,7 +244,7 @@ export class AccessibilityManager extends Disposable {
     }
   }
 
-  private _onKey(keyChar: string): void {
+  private _handleKey(keyChar: string): void {
     this._clearLiveRegion();
     this._charsToConsume.push(keyChar);
   }
@@ -278,7 +278,7 @@ export class AccessibilityManager extends Disposable {
       return;
     }
     if (this._rowElements.length !== this._terminal.rows) {
-      this._onResize(this._terminal.rows);
+      this._handleResize(this._terminal.rows);
     }
     for (let i = 0; i < this._terminal.rows; i++) {
       this._refreshRowDimensions(this._rowElements[i]);

src/browser/Linkifier2.ts

@@ -64,12 +64,12 @@ export class Linkifier2 extends Disposable implements ILinkifier2 {
       this._isMouseOut = true;
       this._clearCurrentLink();
     }));
-    this.register(addDisposableDomListener(this._element, 'mousemove', this._onMouseMove.bind(this)));
+    this.register(addDisposableDomListener(this._element, 'mousemove', this._handleMouseMove.bind(this)));
     this.register(addDisposableDomListener(this._element, 'mousedown', this._handleMouseDown.bind(this)));
     this.register(addDisposableDomListener(this._element, 'mouseup', this._handleMouseUp.bind(this)));
   }
 
-  private _onMouseMove(event: MouseEvent): void {
+  private _handleMouseMove(event: MouseEvent): void {
     this._lastMouseEvent = event;
 
     if (!this._element || !this._mouseService) {
@@ -97,12 +97,12 @@ export class Linkifier2 extends Disposable implements ILinkifier2 {
     }
 
     if (!this._lastBufferCell || (position.x !== this._lastBufferCell.x || position.y !== this._lastBufferCell.y)) {
-      this._onHover(position);
+      this._handleHover(position);
       this._lastBufferCell = position;
     }
   }
 
-  private _onHover(position: IBufferCellPosition): void {
+  private _handleHover(position: IBufferCellPosition): void {
     // TODO: This currently does not cache link provider results across wrapped lines, activeLine should be something like `activeRange: {startY, endY}`
     // Check if we need to clear the link
     if (this._activeLine !== position.y) {

src/browser/Terminal.ts

@@ -316,7 +316,7 @@ export class Terminal extends CoreTerminal implements ITerminal {
   /**
    * Binds the desired focus behavior on a given terminal object.
    */
-  private _onTextAreaFocus(ev: KeyboardEvent): void {
+  private _handleTextAreaFocus(ev: KeyboardEvent): void {
     if (this.coreService.decPrivateModes.sendFocus) {
       this.coreService.triggerDataEvent(C0.ESC + '[I');
     }
@@ -337,7 +337,7 @@ export class Terminal extends CoreTerminal implements ITerminal {
   /**
    * Binds the desired blur behavior on a given terminal object.
    */
-  private _onTextAreaBlur(): void {
+  private _handleTextAreaBlur(): void {
     // Text can safely be removed on blur. Doing it earlier could interfere with
     // screen readers reading it out.
     this.textarea!.value = '';
@@ -488,8 +488,8 @@ export class Terminal extends CoreTerminal implements ITerminal {
     this.textarea.setAttribute('autocapitalize', 'off');
     this.textarea.setAttribute('spellcheck', 'false');
     this.textarea.tabIndex = 0;
-    this.register(addDisposableDomListener(this.textarea, 'focus', (ev: KeyboardEvent) => this._onTextAreaFocus(ev)));
-    this.register(addDisposableDomListener(this.textarea, 'blur', () => this._onTextAreaBlur()));
+    this.register(addDisposableDomListener(this.textarea, 'focus', (ev: KeyboardEvent) => this._handleTextAreaFocus(ev)));
+    this.register(addDisposableDomListener(this.textarea, 'blur', () => this._handleTextAreaBlur()));
     this._helperContainer.appendChild(this.textarea);
 
     this._coreBrowserService = this._instantiationService.createInstance(CoreBrowserService, this.textarea, this._document.defaultView ?? window);

src/browser/Viewport.ts

@@ -65,7 +65,7 @@ export class Viewport extends Disposable implements IViewport {
     // Unfortunately the overlay scrollbar would be hidden underneath the screen element in that case,
     // therefore we account for a standard amount to make it visible
     this.scrollBarWidth = (this._viewportElement.offsetWidth - this._scrollArea.offsetWidth) || FALLBACK_SCROLL_BAR_WIDTH;
-    this.register(addDisposableDomListener(this._viewportElement, 'scroll', this._onScroll.bind(this)));
+    this.register(addDisposableDomListener(this._viewportElement, 'scroll', this._handleScroll.bind(this)));
 
     // Track properties used in performance critical code manually to avoid using slow getters
     this._activeBuffer = this._bufferService.buffer;
@@ -157,7 +157,7 @@ export class Viewport extends Disposable implements IViewport {
    * terminal to scroll to it.
    * @param ev The scroll event.
    */
-  private _onScroll(ev: Event): void {
+  private _handleScroll(ev: Event): void {
     // Record current scroll top position
     this._lastScrollTop = this._viewportElement.scrollTop;
 

src/browser/renderer/dom/DomRenderer.ts

@@ -87,8 +87,8 @@ export class DomRenderer extends Disposable implements IRenderer {
     this._screenElement.appendChild(this._rowContainer);
     this._screenElement.appendChild(this._selectionContainer);
 
-    this.register(this._linkifier2.onShowLinkUnderline(e => this._onLinkHover(e)));
-    this.register(this._linkifier2.onHideLinkUnderline(e => this._onLinkLeave(e)));
+    this.register(this._linkifier2.onShowLinkUnderline(e => this._handleLinkHover(e)));
+    this.register(this._linkifier2.onHideLinkUnderline(e => this._handleLinkLeave(e)));
 
     this.register(toDisposable(() => {
       this._element.classList.remove(TERMINAL_CLASS_PREFIX + this._terminalClass);
@@ -376,11 +376,11 @@ export class DomRenderer extends Disposable implements IRenderer {
     return `.${TERMINAL_CLASS_PREFIX}${this._terminalClass}`;
   }
 
-  private _onLinkHover(e: ILinkifierEvent): void {
+  private _handleLinkHover(e: ILinkifierEvent): void {
     this._setCellUnderline(e.x1, e.x2, e.y1, e.y2, e.cols, true);
   }
 
-  private _onLinkLeave(e: ILinkifierEvent): void {
+  private _handleLinkLeave(e: ILinkifierEvent): void {
     this._setCellUnderline(e.x1, e.x2, e.y1, e.y2, e.cols, false);
   }
 

src/browser/services/RenderService.ts

@@ -92,13 +92,13 @@ export class RenderService extends Disposable implements IRenderService {
     // Detect whether IntersectionObserver is detected and enable renderer pause
     // and resume based on terminal visibility if so
     if ('IntersectionObserver' in coreBrowserService.window) {
-      const observer = new coreBrowserService.window.IntersectionObserver(e => this._onIntersectionChange(e[e.length - 1]), { threshold: 0 });
+      const observer = new coreBrowserService.window.IntersectionObserver(e => this._handleIntersectionChange(e[e.length - 1]), { threshold: 0 });
       observer.observe(screenElement);
       this.register({ dispose: () => observer.disconnect() });
     }
   }
 
-  private _onIntersectionChange(entry: IntersectionObserverEntry): void {
+  private _handleIntersectionChange(entry: IntersectionObserverEntry): void {
     this._isPaused = entry.isIntersecting === undefined ? (entry.intersectionRatio === 0) : !entry.isIntersecting;
 
     // Terminal was hidden on open

src/browser/services/SelectionService.ts

@@ -134,15 +134,15 @@ export class SelectionService extends Disposable implements ISelectionService {
     super();
 
     // Init listeners
-    this._mouseMoveListener = event => this._onMouseMove(event as MouseEvent);
-    this._mouseUpListener = event => this._onMouseUp(event as MouseEvent);
+    this._mouseMoveListener = event => this._handleMouseMove(event as MouseEvent);
+    this._mouseUpListener = event => this._handleMouseUp(event as MouseEvent);
     this._coreService.onUserInput(() => {
       if (this.hasSelection) {
         this.clearSelection();
       }
     });
-    this._trimListener = this._bufferService.buffer.lines.onTrim(amount => this._onTrim(amount));
-    this.register(this._bufferService.buffers.onBufferActivate(e => this._onBufferActivate(e)));
+    this._trimListener = this._bufferService.buffer.lines.onTrim(amount => this._handleTrim(amount));
+    this.register(this._bufferService.buffers.onBufferActivate(e => this._handleBufferActivate(e)));
 
     this.enable();
 
@@ -375,7 +375,7 @@ export class SelectionService extends Disposable implements ISelectionService {
    * Handle the buffer being trimmed, adjust the selection position.
    * @param amount The amount the buffer is being trimmed.
    */
-  private _onTrim(amount: number): void {
+  private _handleTrim(amount: number): void {
     const needsRefresh = this._model.handleTrim(amount);
     if (needsRefresh) {
       this.refresh();
@@ -468,14 +468,14 @@ export class SelectionService extends Disposable implements ISelectionService {
     this._dragScrollAmount = 0;
 
     if (this._enabled && event.shiftKey) {
-      this._onIncrementalClick(event);
+      this._handleIncrementalClick(event);
     } else {
       if (event.detail === 1) {
-        this._onSingleClick(event);
+        this._handleSingleClick(event);
       } else if (event.detail === 2) {
-        this._onDoubleClick(event);
+        this._handleDoubleClick(event);
       } else if (event.detail === 3) {
-        this._onTripleClick(event);
+        this._handleTripleClick(event);
       }
     }
 
@@ -512,7 +512,7 @@ export class SelectionService extends Disposable implements ISelectionService {
    * position.
    * @param event The mouse event.
    */
-  private _onIncrementalClick(event: MouseEvent): void {
+  private _handleIncrementalClick(event: MouseEvent): void {
     if (this._model.selectionStart) {
       this._model.selectionEnd = this._getMouseBufferCoords(event);
     }
@@ -523,7 +523,7 @@ export class SelectionService extends Disposable implements ISelectionService {
    * start position.
    * @param event The mouse event.
    */
-  private _onSingleClick(event: MouseEvent): void {
+  private _handleSingleClick(event: MouseEvent): void {
     this._model.selectionStartLength = 0;
     this._model.isSelectAllActive = false;
     this._activeSelectionMode = this.shouldColumnSelect(event) ? SelectionMode.COLUMN : SelectionMode.NORMAL;
@@ -557,7 +557,7 @@ export class SelectionService extends Disposable implements ISelectionService {
    * Performs a double click, selecting the current word.
    * @param event The mouse event.
    */
-  private _onDoubleClick(event: MouseEvent): void {
+  private _handleDoubleClick(event: MouseEvent): void {
     if (this._selectWordAtCursor(event, true)) {
       this._activeSelectionMode = SelectionMode.WORD;
     }
@@ -568,7 +568,7 @@ export class SelectionService extends Disposable implements ISelectionService {
    * select mode.
    * @param event The mouse event.
    */
-  private _onTripleClick(event: MouseEvent): void {
+  private _handleTripleClick(event: MouseEvent): void {
     const coords = this._getMouseBufferCoords(event);
     if (coords) {
       this._activeSelectionMode = SelectionMode.LINE;
@@ -589,7 +589,7 @@ export class SelectionService extends Disposable implements ISelectionService {
    * end of the selection and refreshing the selection.
    * @param event The mousemove event.
    */
-  private _onMouseMove(event: MouseEvent): void {
+  private _handleMouseMove(event: MouseEvent): void {
     // If the mousemove listener is active it means that a selection is
     // currently being made, we should stop propagation to prevent mouse events
     // to be sent to the pty.
@@ -690,7 +690,7 @@ export class SelectionService extends Disposable implements ISelectionService {
    * Handles the mouseup event, removing the mousedown listeners.
    * @param event The mouseup event.
    */
-  private _onMouseUp(event: MouseEvent): void {
+  private _handleMouseUp(event: MouseEvent): void {
     const timeElapsed = event.timeStamp - this._mouseDownTimeStamp;
 
     this._removeMouseDownListeners();
@@ -746,14 +746,14 @@ export class SelectionService extends Disposable implements ISelectionService {
     this._onSelectionChange.fire();
   }
 
-  private _onBufferActivate(e: {activeBuffer: IBuffer, inactiveBuffer: IBuffer}): void {
+  private _handleBufferActivate(e: {activeBuffer: IBuffer, inactiveBuffer: IBuffer}): void {
     this.clearSelection();
     // Only adjust the selection on trim, shiftElements is rarely used (only in
     // reverseIndex) and delete in a splice is only ever used when the same
     // number of elements was just added. Given this is could actually be
     // beneficial to leave the selection as is for these cases.
     this._trimListener.dispose();
-    this._trimListener = e.activeBuffer.lines.onTrim(amount => this._onTrim(amount));
+    this._trimListener = e.activeBuffer.lines.onTrim(amount => this._handleTrim(amount));
   }
 
   /**