ref: Add no-class-field-initializers eslint rule (#8700)

Adding a lint rule (see
#5316) to enforce
initializing of fields in constructor, to reduce bundle size of
transpiled code (and streamline this a bit overall).

Closes #5316

Author: mydea

packages/angular/src/errorhandler.ts

@@ -83,9 +83,11 @@ class SentryErrorHandler implements AngularErrorHandler {
   protected readonly _options: ErrorHandlerOptions;
 
   /* indicates if we already registered our the afterSendEvent handler */
-  private _registeredAfterSendEventHandler = false;
+  private _registeredAfterSendEventHandler;
 
   public constructor(@Inject('errorHandlerOptions') options?: ErrorHandlerOptions) {
+    this._registeredAfterSendEventHandler = false;
+
     this._options = {
       logErrors: true,
       ...options,

packages/angular/src/tracing.ts

@@ -145,11 +145,14 @@ export class TraceService implements OnDestroy {
     }),
   );
 
-  private _routingSpan: Span | null = null;
+  private _routingSpan: Span | null;
 
-  private _subscription: Subscription = new Subscription();
+  private _subscription: Subscription;
 
   public constructor(private readonly _router: Router) {
+    this._routingSpan = null;
+    this._subscription = new Subscription();
+
     this._subscription.add(this.navStart$.subscribe());
     this._subscription.add(this.resEnd$.subscribe());
     this._subscription.add(this.navEnd$.subscribe());

packages/browser/src/integrations/breadcrumbs.ts

@@ -56,7 +56,7 @@ export class Breadcrumbs implements Integration {
   /**
    * @inheritDoc
    */
-  public name: string = Breadcrumbs.id;
+  public name: string;
 
   /**
    * Options of the breadcrumbs integration.
@@ -68,6 +68,7 @@ export class Breadcrumbs implements Integration {
    * @inheritDoc
    */
   public constructor(options?: Partial<BreadcrumbsOptions>) {
+    this.name = Breadcrumbs.id;
     this.options = {
       console: true,
       dom: true,

packages/browser/src/integrations/dedupe.ts

@@ -11,13 +11,17 @@ export class Dedupe implements Integration {
   /**
    * @inheritDoc
    */
-  public name: string = Dedupe.id;
+  public name: string;
 
   /**
    * @inheritDoc
    */
   private _previousEvent?: Event;
 
+  public constructor() {
+    this.name = Dedupe.id;
+  }
+
   /**
    * @inheritDoc
    */

packages/browser/src/integrations/globalhandlers.ts

@@ -30,7 +30,7 @@ export class GlobalHandlers implements Integration {
   /**
    * @inheritDoc
    */
-  public name: string = GlobalHandlers.id;
+  public name: string;
 
   /** JSDoc */
   private readonly _options: GlobalHandlersIntegrations;
@@ -39,18 +39,21 @@ export class GlobalHandlers implements Integration {
    * Stores references functions to installing handlers. Will set to undefined
    * after they have been run so that they are not used twice.
    */
-  private _installFunc: Record<GlobalHandlersIntegrationsOptionKeys, (() => void) | undefined> = {
-    onerror: _installGlobalOnErrorHandler,
-    onunhandledrejection: _installGlobalOnUnhandledRejectionHandler,
-  };
+  private _installFunc: Record<GlobalHandlersIntegrationsOptionKeys, (() => void) | undefined>;
 
   /** JSDoc */
   public constructor(options?: GlobalHandlersIntegrations) {
+    this.name = GlobalHandlers.id;
     this._options = {
       onerror: true,
       onunhandledrejection: true,
       ...options,
     };
+
+    this._installFunc = {
+      onerror: _installGlobalOnErrorHandler,
+      onunhandledrejection: _installGlobalOnUnhandledRejectionHandler,
+    };
   }
   /**
    * @inheritDoc

packages/browser/src/integrations/httpcontext.ts

@@ -13,7 +13,11 @@ export class HttpContext implements Integration {
   /**
    * @inheritDoc
    */
-  public name: string = HttpContext.id;
+  public name: string;
+
+  public constructor() {
+    this.name = HttpContext.id;
+  }
 
   /**
    * @inheritDoc

packages/browser/src/integrations/linkederrors.ts

@@ -21,7 +21,7 @@ export class LinkedErrors implements Integration {
   /**
    * @inheritDoc
    */
-  public readonly name: string = LinkedErrors.id;
+  public readonly name: string;
 
   /**
    * @inheritDoc
@@ -37,6 +37,7 @@ export class LinkedErrors implements Integration {
    * @inheritDoc
    */
   public constructor(options: Partial<LinkedErrorsOptions> = {}) {
+    this.name = LinkedErrors.id;
     this._key = options.key || DEFAULT_KEY;
     this._limit = options.limit || DEFAULT_LIMIT;
   }

packages/browser/src/integrations/trycatch.ts

@@ -56,7 +56,7 @@ export class TryCatch implements Integration {
   /**
    * @inheritDoc
    */
-  public name: string = TryCatch.id;
+  public name: string;
 
   /** JSDoc */
   private readonly _options: TryCatchOptions;
@@ -65,6 +65,7 @@ export class TryCatch implements Integration {
    * @inheritDoc
    */
   public constructor(options?: Partial<TryCatchOptions>) {
+    this.name = TryCatch.id;
     this._options = {
       XMLHttpRequest: true,
       eventTarget: true,

packages/browser/src/profiling/integration.ts

@@ -22,8 +22,15 @@ import {
  * @experimental
  */
 export class BrowserProfilingIntegration implements Integration {
-  public readonly name: string = 'BrowserProfilingIntegration';
-  public getCurrentHub?: () => Hub = undefined;
+  public static id: string = 'BrowserProfilingIntegration';
+
+  public readonly name: string;
+
+  public getCurrentHub?: () => Hub;
+
+  public constructor() {
+    this.name = BrowserProfilingIntegration.id;
+  }
 
   /**
    * @inheritDoc

packages/core/src/baseclient.ts

@@ -93,19 +93,19 @@ export abstract class BaseClient<O extends ClientOptions> implements Client<O> {
   protected readonly _transport?: Transport;
 
   /** Array of set up integrations. */
-  protected _integrations: IntegrationIndex = {};
+  protected _integrations: IntegrationIndex;
 
   /** Indicates whether this client's integrations have been set up. */
-  protected _integrationsInitialized: boolean = false;
+  protected _integrationsInitialized: boolean;
 
   /** Number of calls being processed */
-  protected _numProcessing: number = 0;
+  protected _numProcessing: number;
 
   /** Holds flushable  */
-  private _outcomes: { [key: string]: number } = {};
+  private _outcomes: { [key: string]: number };
 
   // eslint-disable-next-line @typescript-eslint/ban-types
-  private _hooks: Record<string, Function[]> = {};
+  private _hooks: Record<string, Function[]>;
 
   /**
    * Initializes this client instance.
@@ -114,6 +114,11 @@ export abstract class BaseClient<O extends ClientOptions> implements Client<O> {
    */
   protected constructor(options: O) {
     this._options = options;
+    this._integrations = {};
+    this._integrationsInitialized = false;
+    this._numProcessing = 0;
+    this._outcomes = {};
+    this._hooks = {};
 
     if (options.dsn) {
       this._dsn = makeDsn(options.dsn);

packages/core/src/integrations/functiontostring.ts

@@ -13,7 +13,11 @@ export class FunctionToString implements Integration {
   /**
    * @inheritDoc
    */
-  public name: string = FunctionToString.id;
+  public name: string;
+
+  public constructor() {
+    this.name = FunctionToString.id;
+  }
 
   /**
    * @inheritDoc

packages/core/src/integrations/inboundfilters.ts

@@ -36,9 +36,14 @@ export class InboundFilters implements Integration {
   /**
    * @inheritDoc
    */
-  public name: string = InboundFilters.id;
+  public name: string;
 
-  public constructor(private readonly _options: Partial<InboundFiltersOptions> = {}) {}
+  private readonly _options: Partial<InboundFiltersOptions>;
+
+  public constructor(options: Partial<InboundFiltersOptions> = {}) {
+    this.name = InboundFilters.id;
+    this._options = options;
+  }
 
   /**
    * @inheritDoc

packages/core/src/integrations/metadata.ts

@@ -21,7 +21,11 @@ export class ModuleMetadata implements Integration {
   /**
    * @inheritDoc
    */
-  public name: string = ModuleMetadata.id;
+  public name: string;
+
+  public constructor() {
+    this.name = ModuleMetadata.id;
+  }
 
   /**
    * @inheritDoc

packages/core/src/sessionflusher.ts

@@ -18,15 +18,19 @@ type ReleaseHealthAttributes = {
  * @inheritdoc
  */
 export class SessionFlusher implements SessionFlusherLike {
-  public readonly flushTimeout: number = 60;
-  private _pendingAggregates: Record<number, AggregationCounts> = {};
+  public readonly flushTimeout: number;
+  private _pendingAggregates: Record<number, AggregationCounts>;
   private _sessionAttrs: ReleaseHealthAttributes;
   private _intervalId: ReturnType<typeof setInterval>;
-  private _isEnabled: boolean = true;
+  private _isEnabled: boolean;
   private _client: Client;
 
   public constructor(client: Client, attrs: ReleaseHealthAttributes) {
     this._client = client;
+    this.flushTimeout = 60;
+    this._pendingAggregates = {};
+    this._isEnabled = true;
+
     // Call to setInterval, so that flush is called every 60 seconds
     this._intervalId = setInterval(() => this.flush(), this.flushTimeout * 1000);
     this._sessionAttrs = attrs;

packages/core/src/tracing/idletransaction.ts

@@ -69,28 +69,27 @@ export type BeforeFinishCallback = (transactionSpan: IdleTransaction, endTimesta
  */
 export class IdleTransaction extends Transaction {
   // Activities store a list of active spans
-  public activities: Record<string, boolean> = {};
-
+  public activities: Record<string, boolean>;
   // Track state of activities in previous heartbeat
   private _prevHeartbeatString: string | undefined;
 
   // Amount of times heartbeat has counted. Will cause transaction to finish after 3 beats.
-  private _heartbeatCounter: number = 0;
+  private _heartbeatCounter: number;
 
   // We should not use heartbeat if we finished a transaction
-  private _finished: boolean = false;
+  private _finished: boolean;
 
   // Idle timeout was canceled and we should finish the transaction with the last span end.
-  private _idleTimeoutCanceledPermanently: boolean = false;
+  private _idleTimeoutCanceledPermanently: boolean;
 
-  private readonly _beforeFinishCallbacks: BeforeFinishCallback[] = [];
+  private readonly _beforeFinishCallbacks: BeforeFinishCallback[];
 
   /**
    * Timer that tracks Transaction idleTimeout
    */
   private _idleTimeoutID: ReturnType<typeof setTimeout> | undefined;
 
-  private _finishReason: (typeof IDLE_TRANSACTION_FINISH_REASONS)[number] = IDLE_TRANSACTION_FINISH_REASONS[4];
+  private _finishReason: (typeof IDLE_TRANSACTION_FINISH_REASONS)[number];
 
   public constructor(
     transactionContext: TransactionContext,
@@ -110,6 +109,13 @@ export class IdleTransaction extends Transaction {
   ) {
     super(transactionContext, _idleHub);
 
+    this.activities = {};
+    this._heartbeatCounter = 0;
+    this._finished = false;
+    this._idleTimeoutCanceledPermanently = false;
+    this._beforeFinishCallbacks = [];
+    this._finishReason = IDLE_TRANSACTION_FINISH_REASONS[4];
+
     if (_onScope) {
       // We set the transaction here on the scope so error events pick up the trace
       // context and attach it to the error.

packages/core/src/tracing/span.ts

@@ -16,12 +16,13 @@ import { dropUndefinedKeys, generateSentryTraceHeader, logger, timestampInSecond
  * @hidden
  */
 export class SpanRecorder {
-  public spans: Span[] = [];
+  public spans: Span[];
 
   private readonly _maxlen: number;
 
   public constructor(maxlen: number = 1000) {
     this._maxlen = maxlen;
+    this.spans = [];
   }
 
   /**
@@ -46,12 +47,12 @@ export class Span implements SpanInterface {
   /**
    * @inheritDoc
    */
-  public traceId: string = uuid4();
+  public traceId: string;
 
   /**
    * @inheritDoc
    */
-  public spanId: string = uuid4().substring(16);
+  public spanId: string;
 
   /**
    * @inheritDoc
@@ -71,7 +72,7 @@ export class Span implements SpanInterface {
   /**
    * Timestamp in seconds when the span was created.
    */
-  public startTimestamp: number = timestampInSeconds();
+  public startTimestamp: number;
 
   /**
    * Timestamp in seconds when the span ended.
@@ -91,13 +92,13 @@ export class Span implements SpanInterface {
   /**
    * @inheritDoc
    */
-  public tags: { [key: string]: Primitive } = {};
+  public tags: { [key: string]: Primitive };
 
   /**
    * @inheritDoc
    */
   // eslint-disable-next-line @typescript-eslint/no-explicit-any
-  public data: { [key: string]: any } = {};
+  public data: { [key: string]: any };
 
   /**
    * List of spans that were finalized
@@ -112,7 +113,7 @@ export class Span implements SpanInterface {
   /**
    * The instrumenter that created this span.
    */
-  public instrumenter: Instrumenter = 'sentry';
+  public instrumenter: Instrumenter;
 
   /**
    * You should never call the constructor manually, always use `Sentry.startTransaction()`
@@ -122,6 +123,13 @@ export class Span implements SpanInterface {
    * @hidden
    */
   public constructor(spanContext?: SpanContext) {
+    this.traceId = uuid4();
+    this.spanId = uuid4().substring(16);
+    this.startTimestamp = timestampInSeconds();
+    this.tags = {};
+    this.data = {};
+    this.instrumenter = 'sentry';
+
     if (!spanContext) {
       return this;
     }