Merge pull request #5639 from Tyriar/nullish

Add @typescript-eslint/prefer-nullish-coalescing eslint rule

src/browser/CoreBrowserTerminal.ts

@@ -793,15 +793,15 @@ export class CoreBrowserTerminal extends CoreTerminal implements ITerminal {
       if (!(events & CoreMouseEventType.UP)) {
         this._document!.removeEventListener('mouseup', requestedEvents.mouseup!);
         requestedEvents.mouseup = null;
-      } else if (!requestedEvents.mouseup) {
-        requestedEvents.mouseup = eventListeners.mouseup;
+      } else {
+        requestedEvents.mouseup ??= eventListeners.mouseup;
       }
 
       if (!(events & CoreMouseEventType.DRAG)) {
         this._document!.removeEventListener('mousemove', requestedEvents.mousedrag!);
         requestedEvents.mousedrag = null;
-      } else if (!requestedEvents.mousedrag) {
-        requestedEvents.mousedrag = eventListeners.mousedrag;
+      } else {
+        requestedEvents.mousedrag ??= eventListeners.mousedrag;
       }
     }));
     // force initial onProtocolChange so we dont miss early mouse requests

src/browser/RenderDebouncer.ts

@@ -40,8 +40,8 @@ export class RenderDebouncer implements IRenderDebouncerWithCallback {
   public refresh(rowStart: number | undefined, rowEnd: number | undefined, rowCount: number): void {
     this._rowCount = rowCount;
     // Get the min/max row start/end for the arg values
-    rowStart = rowStart !== undefined ? rowStart : 0;
-    rowEnd = rowEnd !== undefined ? rowEnd : this._rowCount - 1;
+    rowStart = rowStart ?? 0;
+    rowEnd = rowEnd ?? this._rowCount - 1;
     // Set the properties to the updated values
     this._rowStart = this._rowStart !== undefined ? Math.min(this._rowStart, rowStart) : rowStart;
     this._rowEnd = this._rowEnd !== undefined ? Math.max(this._rowEnd, rowEnd) : rowEnd;

src/browser/TimeBasedDebouncer.ts

@@ -37,8 +37,8 @@ export class TimeBasedDebouncer implements IRenderDebouncer {
   public refresh(rowStart: number | undefined, rowEnd: number | undefined, rowCount: number): void {
     this._rowCount = rowCount;
     // Get the min/max row start/end for the arg values
-    rowStart = rowStart !== undefined ? rowStart : 0;
-    rowEnd = rowEnd !== undefined ? rowEnd : this._rowCount - 1;
+    rowStart = rowStart ?? 0;
+    rowEnd = rowEnd ?? this._rowCount - 1;
     // Set the properties to the updated values
     this._rowStart = this._rowStart !== undefined ? Math.min(this._rowStart, rowStart) : rowStart;
     this._rowEnd = this._rowEnd !== undefined ? Math.max(this._rowEnd, rowEnd) : rowEnd;

src/browser/public/Terminal.ts

@@ -84,10 +84,7 @@ export class Terminal extends Disposable implements ITerminalApi {
 
   public get element(): HTMLElement | undefined { return this._core.element; }
   public get parser(): IParser {
-    if (!this._parser) {
-      this._parser = new ParserApi(this._core);
-    }
-    return this._parser;
+    return this._parser ??= new ParserApi(this._core);
   }
   public get unicode(): IUnicodeHandling {
     this._checkProposedApi();
@@ -97,10 +94,7 @@ export class Terminal extends Disposable implements ITerminalApi {
   public get rows(): number { return this._core.rows; }
   public get cols(): number { return this._core.cols; }
   public get buffer(): IBufferNamespaceApi {
-    if (!this._buffer) {
-      this._buffer = this._register(new BufferNamespaceApi(this._core));
-    }
-    return this._buffer;
+    return this._buffer ??= this._register(new BufferNamespaceApi(this._core));
   }
   public get markers(): ReadonlyArray<IMarker> {
     return this._core.markers;

src/browser/renderer/dom/DomRendererRowFactory.ts

@@ -494,8 +494,8 @@ export class DomRendererRowFactory {
       // Dim cells only require half the contrast, otherwise they wouldn't be distinguishable from
       // non-dim cells
       const ratio = this._optionsService.rawOptions.minimumContrastRatio / (cell.isDim() ? 2 : 1);
-      adjustedColor = color.ensureContrastRatio(bgOverride || bg, fgOverride || fg, ratio);
-      cache.setColor((bgOverride || bg).rgba, (fgOverride || fg).rgba, adjustedColor ?? null);
+      adjustedColor = color.ensureContrastRatio(bgOverride ?? bg, fgOverride ?? fg, ratio);
+      cache.setColor((bgOverride ?? bg).rgba, (fgOverride ?? fg).rgba, adjustedColor ?? null);
     }
 
     if (adjustedColor) {

src/browser/services/KeyboardService.ts

@@ -24,16 +24,12 @@ export class KeyboardService implements IKeyboardService {
   }
 
   private _getWin32InputMode(): Win32InputMode {
-    if (!this._win32InputMode) {
-      this._win32InputMode = new Win32InputMode();
-    }
+    this._win32InputMode ??= new Win32InputMode();
     return this._win32InputMode;
   }
 
   private _getKittyKeyboard(): KittyKeyboard {
-    if (!this._kittyKeyboard) {
-      this._kittyKeyboard = new KittyKeyboard();
-    }
+    this._kittyKeyboard ??= new KittyKeyboard();
     return this._kittyKeyboard;
   }
 

src/browser/services/RenderService.ts

@@ -347,13 +347,11 @@ class SynchronizedOutputHandler {
       this._end = Math.max(this._end, end);
     }
 
-    if (this._timeout === undefined) {
-      this._timeout = this._coreBrowserService.window.setTimeout(() => {
-        this._timeout = undefined;
-        this._coreService.decPrivateModes.synchronizedOutput = false;
-        this._onTimeout();
-      }, Constants.SYNCHRONIZED_OUTPUT_TIMEOUT_MS);
-    }
+    this._timeout ??= this._coreBrowserService.window.setTimeout(() => {
+      this._timeout = undefined;
+      this._coreService.decPrivateModes.synchronizedOutput = false;
+      this._onTimeout();
+    }, Constants.SYNCHRONIZED_OUTPUT_TIMEOUT_MS);
   }
 
   public flush(): { start: number, end: number } | undefined {

src/common/Event.ts

@@ -18,33 +18,34 @@ export class Emitter<T> {
   private _event: IEvent<T> | undefined;
 
   public get event(): IEvent<T> {
-    if (!this._event) {
-      this._event = (listener: (e: T) => any, thisArgs?: any, disposables?: IDisposable[] | DisposableStore) => {
-        if (this._disposed) {
-          return toDisposable(() => {});
-        }
-
-        const entry = { fn: listener, thisArgs };
-        this._listeners.push(entry);
-
-        const result = toDisposable(() => {
-          const idx = this._listeners.indexOf(entry);
-          if (idx !== -1) {
-            this._listeners.splice(idx, 1);
-          }
-        });
-
-        if (disposables) {
-          if (Array.isArray(disposables)) {
-            disposables.push(result);
-          } else {
-            disposables.add(result);
-          }
-        }
-
-        return result;
-      };
+    if (this._event) {
+      return this._event;
     }
+    this._event = (listener: (e: T) => any, thisArgs?: any, disposables?: IDisposable[] | DisposableStore) => {
+      if (this._disposed) {
+        return toDisposable(() => {});
+      }
+
+      const entry = { fn: listener, thisArgs };
+      this._listeners.push(entry);
+
+      const result = toDisposable(() => {
+        const idx = this._listeners.indexOf(entry);
+        if (idx !== -1) {
+          this._listeners.splice(idx, 1);
+        }
+      });
+
+      if (disposables) {
+        if (Array.isArray(disposables)) {
+          disposables.push(result);
+        } else {
+          disposables.add(result);
+        }
+      }
+
+      return result;
+    };
     return this._event;
   }
 

src/common/InputHandler.ts

@@ -3343,7 +3343,7 @@ export class InputHandler extends Disposable implements IInputHandler {
     if (collectAndFlag[0] === '/') {
       return true;  // TODO: Is this supported?
     }
-    this._charsetService.setgCharset(GLEVEL[collectAndFlag[0]], CHARSETS[collectAndFlag[1]] || DEFAULT_CHARSET);
+    this._charsetService.setgCharset(GLEVEL[collectAndFlag[0]], CHARSETS[collectAndFlag[1]] ?? DEFAULT_CHARSET);
     return true;
   }
 

src/common/buffer/Buffer.ts

@@ -122,9 +122,7 @@ export class Buffer implements IBuffer {
    */
   public fillViewportRows(fillAttr?: IAttributeData): void {
     if (this.lines.length === 0) {
-      if (fillAttr === undefined) {
-        fillAttr = DEFAULT_ATTR_DATA;
-      }
+      fillAttr ??= DEFAULT_ATTR_DATA;
       let i = this._rows;
       while (i--) {
         this.lines.push(this.getBlankLine(fillAttr));
@@ -589,9 +587,7 @@ export class Buffer implements IBuffer {
    * @param x The position to move the cursor to the previous tab stop.
    */
   public prevStop(x?: number): number {
-    if (x === null || x === undefined) {
-      x = this.x;
-    }
+    x ??= this.x;
     while (!this.tabs[--x] && x > 0);
     return x >= this._cols ? this._cols - 1 : x < 0 ? 0 : x;
   }
@@ -601,9 +597,7 @@ export class Buffer implements IBuffer {
    * @param x The position to move the cursor one tab stop forward.
    */
   public nextStop(x?: number): number {
-    if (x === null || x === undefined) {
-      x = this.x;
-    }
+    x ??= this.x;
     while (!this.tabs[++x] && x < this._cols);
     return x >= this._cols ? this._cols - 1 : x < 0 ? 0 : x;
   }

src/common/buffer/BufferLine.ts

@@ -66,7 +66,7 @@ export class BufferLine implements IBufferLine {
 
   constructor(cols: number, fillCellData?: ICellData, public isWrapped: boolean = false) {
     this._data = new Uint32Array(cols * CELL_SIZE);
-    const cell = fillCellData || CellData.fromCharData([0, NULL_CELL_CHAR, NULL_CELL_WIDTH, NULL_CELL_CODE]);
+    const cell = fillCellData ?? CellData.fromCharData([0, NULL_CELL_CHAR, NULL_CELL_WIDTH, NULL_CELL_CODE]);
     for (let i = 0; i < cols; ++i) {
       this.setCell(i, cell);
     }

src/common/input/Keyboard.test.ts

@@ -26,7 +26,7 @@ function testEvaluateKeyboardEvent(partialEvent: {
     ctrlKey: partialEvent.ctrlKey || false,
     shiftKey: partialEvent.shiftKey || false,
     metaKey: partialEvent.metaKey || false,
-    keyCode: partialEvent.keyCode !== undefined ? partialEvent.keyCode : 0,
+    keyCode: partialEvent.keyCode ?? 0,
     code: partialEvent.code || '',
     key: partialEvent.key || '',
     type: partialEvent.type || ''

src/common/input/KittyKeyboard.test.ts

@@ -9,7 +9,7 @@ function createEvent(partialEvent: Partial<IKeyboardEvent> = {}): IKeyboardEvent
     ctrlKey: partialEvent.ctrlKey || false,
     shiftKey: partialEvent.shiftKey || false,
     metaKey: partialEvent.metaKey || false,
-    keyCode: partialEvent.keyCode !== undefined ? partialEvent.keyCode : 0,
+    keyCode: partialEvent.keyCode ?? 0,
     code: partialEvent.code || '',
     key: partialEvent.key || '',
     type: partialEvent.type || 'keydown'

src/common/input/UnicodeV6.test.ts

@@ -169,7 +169,7 @@ it('wcwidth should match all values from the old implementation', function(): vo
       if (num < 127) {
         return 1;
       }
-      const t = table || initTable();
+      const t = table ?? initTable();
       if (num < 65536) {
         return t[num >> 4] >> ((num & 15) << 1) & 3;
       }

src/common/parser/ApcParser.ts

@@ -36,9 +36,7 @@ export class ApcParser implements IApcParser {
    * @param handler The handler to register
    */
   public registerHandler(ident: number, handler: IApcHandler): IDisposable {
-    if (this._handlers[ident] === undefined) {
-      this._handlers[ident] = [];
-    }
+    this._handlers[ident] ??= [];
     const handlerList = this._handlers[ident];
     handlerList.push(handler);
     return {

src/common/parser/DcsParser.ts

@@ -29,9 +29,7 @@ export class DcsParser implements IDcsParser {
   }
 
   public registerHandler(ident: number, handler: IDcsHandler): IDisposable {
-    if (this._handlers[ident] === undefined) {
-      this._handlers[ident] = [];
-    }
+    this._handlers[ident] ??= [];
     const handlerList = this._handlers[ident];
     handlerList.push(handler);
     return {

src/common/parser/EscapeSequenceParser.ts

@@ -362,9 +362,7 @@ export class EscapeSequenceParser extends Disposable implements IEscapeSequenceP
 
   public registerEscHandler(id: IFunctionIdentifier, handler: EscHandlerType): IDisposable {
     const ident = this._identifier(id, [0x30, 0x7e]);
-    if (this._escHandlers[ident] === undefined) {
-      this._escHandlers[ident] = [];
-    }
+    this._escHandlers[ident] ??= [];
     const handlerList = this._escHandlers[ident];
     handlerList.push(handler);
     return {
@@ -395,9 +393,7 @@ export class EscapeSequenceParser extends Disposable implements IEscapeSequenceP
 
   public registerCsiHandler(id: IFunctionIdentifier, handler: CsiHandlerType): IDisposable {
     const ident = this._identifier(id);
-    if (this._csiHandlers[ident] === undefined) {
-      this._csiHandlers[ident] = [];
-    }
+    this._csiHandlers[ident] ??= [];
     const handlerList = this._csiHandlers[ident];
     handlerList.push(handler);
     return {

src/common/parser/OscParser.ts

@@ -23,9 +23,7 @@ export class OscParser implements IOscParser {
   };
 
   public registerHandler(ident: number, handler: IOscHandler): IDisposable {
-    if (this._handlers[ident] === undefined) {
-      this._handlers[ident] = [];
-    }
+    this._handlers[ident] ??= [];
     const handlerList = this._handlers[ident];
     handlerList.push(handler);
     return {

src/headless/public/Terminal.ts

@@ -84,9 +84,7 @@ export class Terminal extends Disposable implements ITerminalApi {
   public get onWriteParsed(): IEvent<void> { return this._core.onWriteParsed; }
 
   public get parser(): IParser {
-    if (!this._parser) {
-      this._parser = new ParserApi(this._core);
-    }
+    this._parser ??= new ParserApi(this._core);
     return this._parser;
   }
   public get unicode(): IUnicodeHandling {
@@ -96,9 +94,7 @@ export class Terminal extends Disposable implements ITerminalApi {
   public get rows(): number { return this._core.rows; }
   public get cols(): number { return this._core.cols; }
   public get buffer(): IBufferNamespaceApi {
-    if (!this._buffer) {
-      this._buffer = this._register(new BufferNamespaceApi(this._core));
-    }
+    this._buffer ??= this._register(new BufferNamespaceApi(this._core));
     return this._buffer;
   }
   public get markers(): ReadonlyArray<IMarker> {