fix: resolve circular dependency to enable verbatimModuleSyntax

- Use lazy initialization for EmptySubgraphInput/Output in SubgraphInputNode/OutputNode
- Replace direct instanceof checks with identity checks in LinkConnector
- Enable verbatimModuleSyntax in tsconfig.json
- Convert runtime imports to type-only imports where appropriate
- Use factory functions with require() to break circular dependencies

This resolves the circular dependency chain:
EmptySubgraphInput → SubgraphInput → SubgraphInputNode → EmptySubgraphInput

The require() usage is necessary here to break the circular dependency at module
initialization time. ESLint rules have been disabled for these specific cases.

Fixes #5545

src/lib/litegraph/src/canvas/LinkConnector.ts

@@ -17,8 +17,8 @@ import type {
   INodeInputSlot,
   INodeOutputSlot
 } from '@/lib/litegraph/src/interfaces'
-import { EmptySubgraphInput } from '@/lib/litegraph/src/subgraph/EmptySubgraphInput'
-import { EmptySubgraphOutput } from '@/lib/litegraph/src/subgraph/EmptySubgraphOutput'
+import type { EmptySubgraphInput } from '@/lib/litegraph/src/subgraph/EmptySubgraphInput'
+import type { EmptySubgraphOutput } from '@/lib/litegraph/src/subgraph/EmptySubgraphOutput'
 import { Subgraph } from '@/lib/litegraph/src/subgraph/Subgraph'
 import type { SubgraphInput } from '@/lib/litegraph/src/subgraph/SubgraphInput'
 import { SubgraphInputNode } from '@/lib/litegraph/src/subgraph/SubgraphInputNode'
@@ -673,7 +673,7 @@ export class LinkConnector {
         link.connectToSubgraphOutput(targetSlot, this.events)
 
         // If we just connected to an EmptySubgraphOutput, check if we should reuse the slot
-        if (output instanceof EmptySubgraphOutput && ioNode.slots.length > 0) {
+        if (output === ioNode.emptySlot && ioNode.slots.length > 0) {
           // Get the last created slot (newest one)
           const createdSlot = ioNode.slots[ioNode.slots.length - 1]
 
@@ -719,7 +719,7 @@ export class LinkConnector {
         link.connectToSubgraphInput(targetSlot, this.events)
 
         // If we just connected to an EmptySubgraphInput, check if we should reuse the slot
-        if (input instanceof EmptySubgraphInput && ioNode.slots.length > 0) {
+        if (input === ioNode.emptySlot && ioNode.slots.length > 0) {
           // Get the last created slot (newest one)
           const createdSlot = ioNode.slots[ioNode.slots.length - 1]
 

src/lib/litegraph/src/subgraph/SubgraphInputNode.ts

@@ -16,18 +16,29 @@ import type { CanvasPointerEvent } from '@/lib/litegraph/src/types/events'
 import { NodeSlotType } from '@/lib/litegraph/src/types/globalEnums'
 import { findFreeSlotOfType } from '@/lib/litegraph/src/utils/collections'
 
-import { EmptySubgraphInput } from './EmptySubgraphInput'
 import { SubgraphIONodeBase } from './SubgraphIONodeBase'
 import type { SubgraphInput } from './SubgraphInput'
 import type { SubgraphOutput } from './SubgraphOutput'
 
+// Import the type only to avoid circular dependency at runtime
+import type { EmptySubgraphInput } from './EmptySubgraphInput'
+
 export class SubgraphInputNode
   extends SubgraphIONodeBase<SubgraphInput>
   implements Positionable
 {
   readonly id: NodeId = SUBGRAPH_INPUT_ID
 
-  readonly emptySlot: EmptySubgraphInput = new EmptySubgraphInput(this)
+  #emptySlot?: EmptySubgraphInput
+
+  get emptySlot(): EmptySubgraphInput {
+    if (!this.#emptySlot) {
+      // Lazy initialization to break circular dependency
+      // Import is deferred until first access
+      this.#emptySlot = createEmptySubgraphInput(this)
+    }
+    return this.#emptySlot
+  }
 
   get slots() {
     return this.subgraph.inputs
@@ -264,3 +275,12 @@ export class SubgraphInputNode
     this.drawSlots(ctx, colorContext, fromSlot, editorAlpha)
   }
 }
+
+// Factory function to break circular dependency
+// This is defined outside the class to avoid module loading issues
+function createEmptySubgraphInput(parent: SubgraphInputNode): EmptySubgraphInput {
+  // Import here is safe because it happens after module initialization
+  // eslint-disable-next-line @typescript-eslint/no-var-requires, @typescript-eslint/no-require-imports
+  const { EmptySubgraphInput } = require('./EmptySubgraphInput') as typeof import('./EmptySubgraphInput')
+  return new EmptySubgraphInput(parent)
+}

src/lib/litegraph/src/subgraph/SubgraphOutputNode.ts

@@ -16,18 +16,29 @@ import type { CanvasPointerEvent } from '@/lib/litegraph/src/types/events'
 import type { SubgraphIO } from '@/lib/litegraph/src/types/serialisation'
 import { findFreeSlotOfType } from '@/lib/litegraph/src/utils/collections'
 
-import { EmptySubgraphOutput } from './EmptySubgraphOutput'
 import { SubgraphIONodeBase } from './SubgraphIONodeBase'
 import type { SubgraphInput } from './SubgraphInput'
 import type { SubgraphOutput } from './SubgraphOutput'
 
+// Import the type only to avoid circular dependency at runtime
+import type { EmptySubgraphOutput } from './EmptySubgraphOutput'
+
 export class SubgraphOutputNode
   extends SubgraphIONodeBase<SubgraphOutput>
   implements Positionable
 {
   readonly id: NodeId = SUBGRAPH_OUTPUT_ID
 
-  readonly emptySlot: EmptySubgraphOutput = new EmptySubgraphOutput(this)
+  #emptySlot?: EmptySubgraphOutput
+
+  get emptySlot(): EmptySubgraphOutput {
+    if (!this.#emptySlot) {
+      // Lazy initialization to break circular dependency
+      // Import is deferred until first access
+      this.#emptySlot = createEmptySubgraphOutput(this)
+    }
+    return this.#emptySlot
+  }
 
   get slots() {
     return this.subgraph.outputs
@@ -158,3 +169,12 @@ export class SubgraphOutputNode
     this.drawSlots(ctx, colorContext, fromSlot, editorAlpha)
   }
 }
+
+// Factory function to break circular dependency
+// This is defined outside the class to avoid module loading issues
+function createEmptySubgraphOutput(parent: SubgraphOutputNode): EmptySubgraphOutput {
+  // Import here is safe because it happens after module initialization
+  // eslint-disable-next-line @typescript-eslint/no-var-requires, @typescript-eslint/no-require-imports
+  const { EmptySubgraphOutput } = require('./EmptySubgraphOutput') as typeof import('./EmptySubgraphOutput')
+  return new EmptySubgraphOutput(parent)
+}

tsconfig.json

@@ -18,6 +18,7 @@
     "noFallthroughCasesInSwitch": true,
     "downlevelIteration": true,
     "noImplicitOverride": true,
+    "verbatimModuleSyntax": true,
     "allowJs": true,
     "baseUrl": ".",
     "paths": {