refactor(@ngtools/webpack): remove unneeded transform operation types

The transform operation types are currently only used and returned by the import elider but are immediately mapped back to the underlying TypeScript node at import elider callsites.
This change also switches the import elider to return a Set to reduce the overhead of repeated array `includes` calls.

Author: clydin

packages/ngtools/webpack/src/ivy/transformation.ts

@@ -132,11 +132,11 @@ export function replaceBootstrap(
           replacedNodes,
           getTypeChecker,
           context.getCompilerOptions(),
-        ).map((op) => op.target);
-        if (removals.length > 0) {
+        );
+        if (removals.size > 0) {
           updatedSourceFile = ts.visitEachChild(
             updatedSourceFile,
-            (node) => (removals.includes(node) ? undefined : node),
+            (node) => (removals.has(node) ? undefined : node),
             context,
           );
         }

packages/ngtools/webpack/src/transformers/elide_imports.ts

@@ -7,7 +7,6 @@
  */
 
 import * as ts from 'typescript';
-import { RemoveNodeOperation, TransformOperation } from './interfaces';
 
 // Remove imports for which all identifiers have been removed.
 // Needs type checker, and works even if it's not the first transformer.
@@ -20,11 +19,11 @@ export function elideImports(
   removedNodes: ts.Node[],
   getTypeChecker: () => ts.TypeChecker,
   compilerOptions: ts.CompilerOptions,
-): TransformOperation[] {
-  const ops: TransformOperation[] = [];
+): Set<ts.Node> {
+  const importNodeRemovals = new Set<ts.Node>();
 
   if (removedNodes.length === 0) {
-    return [];
+    return importNodeRemovals;
   }
 
   const typeChecker = getTypeChecker();
@@ -117,7 +116,7 @@ export function elideImports(
   });
 
   if (imports.length === 0) {
-    return [];
+    return importNodeRemovals;
   }
 
   const isUnused = (node: ts.Identifier) => {
@@ -142,10 +141,10 @@ export function elideImports(
     if (namedBindings && ts.isNamespaceImport(namedBindings)) {
       // "import * as XYZ from 'abc';"
       if (isUnused(namedBindings.name)) {
-        ops.push(new RemoveNodeOperation(sourceFile, node));
+        importNodeRemovals.add(node);
       }
     } else {
-      const specifierOps = [];
+      const specifierNodeRemovals = [];
       let clausesCount = 0;
 
       // "import { XYZ, ... } from 'abc';"
@@ -160,7 +159,7 @@ export function elideImports(
             const nodeToRemove =
               clausesCount === removedClausesCount ? specifier.parent : specifier;
 
-            specifierOps.push(new RemoveNodeOperation(sourceFile, nodeToRemove));
+            specifierNodeRemovals.push(nodeToRemove);
           }
         }
       }
@@ -170,17 +169,19 @@ export function elideImports(
         clausesCount++;
 
         if (isUnused(node.importClause.name)) {
-          specifierOps.push(new RemoveNodeOperation(sourceFile, node.importClause.name));
+          specifierNodeRemovals.push(node.importClause.name);
         }
       }
 
-      if (specifierOps.length === clausesCount) {
-        ops.push(new RemoveNodeOperation(sourceFile, node));
+      if (specifierNodeRemovals.length === clausesCount) {
+        importNodeRemovals.add(node);
       } else {
-        ops.push(...specifierOps);
+        for (const specifierNodeRemoval of specifierNodeRemovals) {
+          importNodeRemovals.add(specifierNodeRemoval);
+        }
       }
     }
   }
 
-  return ops;
+  return importNodeRemovals;
 }

packages/ngtools/webpack/src/transformers/elide_imports_spec.ts

@@ -34,12 +34,12 @@ describe('@ngtools/webpack transformers', () => {
             [lastNode],
             () => program.getTypeChecker(),
             context.getCompilerOptions(),
-          ).map((op) => op.target);
-          if (importRemovals.length > 0) {
+          );
+          if (importRemovals.size > 0) {
             return ts.visitEachChild(
               updatedSourceFile,
               function visitForRemoval(node): ts.Node | undefined {
-                return importRemovals.includes(node)
+                return importRemovals.has(node)
                   ? undefined
                   : ts.visitEachChild(node, visitForRemoval, context);
               },

packages/ngtools/webpack/src/transformers/interfaces.ts

@@ -55,12 +55,12 @@ export function removeIvyJitSupportCalls(
           removedNodes,
           getTypeChecker,
           context.getCompilerOptions(),
-        ).map((op) => op.target);
-        if (importRemovals.length > 0) {
+        );
+        if (importRemovals.size > 0) {
           updatedSourceFile = ts.visitEachChild(
             updatedSourceFile,
             function visitForRemoval(node): ts.Node | undefined {
-              return importRemovals.includes(node)
+              return importRemovals.has(node)
                 ? undefined
                 : ts.visitEachChild(node, visitForRemoval, context);
             },