fix(ngcc): handle CommonJS re-exports by reference (#34254)

In TS we can re-export imports using statements of the form:

```
export * from 'some-import';
```

This can be downleveled in CommonJS to either:

```
__export(require('some-import'));
```

or

```
var someImport = require('some-import');
__export(someImport);
```

Previously we only supported the first downleveled version.
This commit adds support for the second version.

PR Close #34254

packages/compiler-cli/ngcc/src/host/commonjs_host.ts

@@ -137,24 +137,35 @@ export class CommonJsReflectionHost extends Esm5ReflectionHost {
 
   private extractCommonJsReexports(statement: ReexportStatement, containingFile: ts.SourceFile):
       CommonJsExportDeclaration[] {
-    const reexports: CommonJsExportDeclaration[] = [];
+    const reexportArg = statement.expression.arguments[0];
-    const requireCall = statement.expression.arguments[0];
+
+    const requireCall = isRequireCall(reexportArg) ?
+        reexportArg :
+        ts.isIdentifier(reexportArg) ? this.findRequireCallReference(reexportArg) : null;
+    if (requireCall === null) {
+      return [];
+    }
+
     const importPath = requireCall.arguments[0].text;
     const importedFile = this.resolveModuleName(importPath, containingFile);
-    if (importedFile !== undefined) {
+    if (importedFile === undefined) {
+      return [];
+    }
+
     const viaModule = stripExtension(importedFile.fileName);
     const importedExports = this.getExportsOfModule(importedFile);
-      if (importedExports !== null) {
+    if (importedExports === null) {
+      return [];
+    }
+
+    const reexports: CommonJsExportDeclaration[] = [];
     importedExports.forEach((decl, name) => {
       if (decl.node !== null) {
         reexports.push({name, declaration: {node: decl.node, viaModule}});
       } else {
-            reexports.push(
+        reexports.push({name, declaration: {node: null, expression: decl.expression, viaModule}});
-                {name, declaration: {node: null, expression: decl.expression, viaModule}});
       }
     });
-      }
-    }
     return reexports;
   }
 
@@ -162,11 +173,14 @@ export class CommonJsReflectionHost extends Esm5ReflectionHost {
     // Is `id` a namespaced property access, e.g. `Directive` in `core.Directive`?
     // If so capture the symbol of the namespace, e.g. `core`.
     const nsIdentifier = findNamespaceOfIdentifier(id);
-    const nsSymbol = nsIdentifier && this.checker.getSymbolAtLocation(nsIdentifier) || null;
+    return nsIdentifier && this.findRequireCallReference(nsIdentifier);
-    const nsDeclaration = nsSymbol && nsSymbol.valueDeclaration;
+  }
+
+  private findRequireCallReference(id: ts.Identifier): RequireCall|null {
+    const symbol = id && this.checker.getSymbolAtLocation(id) || null;
+    const declaration = symbol && symbol.valueDeclaration;
     const initializer =
-        nsDeclaration && ts.isVariableDeclaration(nsDeclaration) && nsDeclaration.initializer ||
+        declaration && ts.isVariableDeclaration(declaration) && declaration.initializer || null;
-        null;
     return initializer && isRequireCall(initializer) ? initializer : null;
   }
 
@@ -237,13 +251,12 @@ function findNamespaceOfIdentifier(id: ts.Identifier): ts.Identifier|null {
       null;
 }
 
-type ReexportStatement = ts.ExpressionStatement & {expression: {arguments: [RequireCall]}};
+type ReexportStatement = ts.ExpressionStatement & {expression: ts.CallExpression};
 function isReexportStatement(statement: ts.Statement): statement is ReexportStatement {
   return ts.isExpressionStatement(statement) && ts.isCallExpression(statement.expression) &&
       ts.isIdentifier(statement.expression.expression) &&
       statement.expression.expression.text === '__export' &&
-      statement.expression.arguments.length === 1 &&
+      statement.expression.arguments.length === 1;
-      isRequireCall(statement.expression.arguments[0]);
 }
 
 function stripExtension(fileName: string): string {

packages/compiler-cli/ngcc/test/host/commonjs_host_spec.ts

@@ -557,7 +557,8 @@ exports.xtra2 = xtra2;
     function __export(m) {
       for (var p in m) if (!exports.hasOwnProperty(p)) exports[p] = m[p];
     }
-    __export(require("./b_module"));
+    var b_module = require("./b_module");
+    __export(b_module);
     __export(require("./xtra_module"));
     `
         },