fix(ivy): move setClassMetadata calls into a pure iife (#33337)

This commit transforms the setClassMetadata calls generated by ngtsc from:

```typescript
/*@__PURE__*/ setClassMetadata(...);
```

to:

```typescript
/*@__PURE__*/ (function() {
  setClassMetadata(...);
})();
```

Without the IIFE, terser won't remove these function calls because the
function calls have arguments that themselves are function calls or other
impure expressions. In order to make the whole block be DCE-ed by terser,
we wrap it into IIFE and mark the IIFE as pure.

It should be noted that this change doesn't have any impact on CLI* with
build-optimizer, which removes the whole setClassMetadata block within
the webpack loader, so terser or webpack itself don't get to see it at
all. This is done to prevent cross-chunk retention issues caused by
webpack's internal module registry.

* actually we do expect a short-term size regression while
angular/angular-cli#16228
is merged and released in the next rc of the CLI. But long term this
change does nothing to CLI + build-optimizer configuration and is done
primarly to correct the seemingly correct but non-function PURE annotation
that builds not using build-optimizer could rely on.

PR Close #33337

aio/scripts/_payload-limits.json

@@ -12,7 +12,7 @@
     "master": {
       "uncompressed": {
         "runtime-es2015": 2987,
-        "main-es2015": 461159,
+        "main-es2015": 506857,
         "polyfills-es2015": 52503
       }
     }

integration/_payload-limits.json

@@ -39,7 +39,7 @@
     "master": {
       "uncompressed": {
         "runtime-es2015": 2289,
-        "main-es2015": 268404,
+        "main-es2015": 312772,
         "polyfills-es2015": 36808,
         "5-es2015": 751
       }

packages/compiler-cli/ngcc/test/integration/ngcc_spec.ts

@@ -139,10 +139,10 @@ runInEachFileSystem(() => {
       const jsContents = fs.readFile(_(`/node_modules/test-package/index.js`)).replace(/\s+/g, ' ');
       expect(jsContents)
           .toContain(
-              '/*@__PURE__*/ ɵngcc0.ɵsetClassMetadata(FooDirective, ' +
+              '/*@__PURE__*/ (function () { ɵngcc0.ɵsetClassMetadata(FooDirective, ' +
               '[{ type: Directive, args: [{ selector: \'[foo]\' }] }], ' +
               'function () { return []; }, ' +
-              '{ bar: [{ type: Input }] });');
+              '{ bar: [{ type: Input }] }); })();');
     });
 
     it('should not add `const` in ES5 generated code', () => {

packages/compiler-cli/ngcc/test/rendering/renderer_spec.ts

@@ -222,10 +222,10 @@ A.ɵcmp = ɵngcc0.ɵɵdefineComponent({ type: A, selectors: [["a"]], decls: 1, v
 
         const addAdjacentStatementsSpy = testFormatter.addAdjacentStatements as jasmine.Spy;
         expect(addAdjacentStatementsSpy.calls.first().args[2]).toEqual(`// TRANSPILED
-/*@__PURE__*/ ɵngcc0.ɵsetClassMetadata(A, [{
+/*@__PURE__*/ (function () { ɵngcc0.ɵsetClassMetadata(A, [{
         type: Component,
         args: [{ selector: 'a', template: '{{ person!.name }}' }]
-    }], null, null);`);
+    }], null, null); })();`);
       });
 
 
@@ -274,10 +274,10 @@ A.ɵdir = ɵngcc0.ɵɵdefineDirective({ type: A, selectors: [["", "a", ""]] });`
                  .toEqual(jasmine.objectContaining(
                      {name: 'A', decorators: [jasmine.objectContaining({name: 'Directive'})]}));
              expect(addAdjacentStatementsSpy.calls.first().args[2]).toEqual(`// TRANSPILED
-/*@__PURE__*/ ɵngcc0.ɵsetClassMetadata(A, [{
+/*@__PURE__*/ (function () { ɵngcc0.ɵsetClassMetadata(A, [{
         type: Directive,
         args: [{ selector: '[a]' }]
-    }], null, null);`);
+    }], null, null); })();`);
            });
 
         it('should call removeDecorators with the source code, a map of class decorators that have been analyzed',
@@ -568,7 +568,7 @@ UndecoratedBase.ɵdir = ɵngcc0.ɵɵdefineDirective({ type: UndecoratedBase, vie
               decorationAnalyses, switchMarkerAnalyses, privateDeclarationsAnalyses);
           const addAdjacentStatementsSpy = testFormatter.addAdjacentStatements as jasmine.Spy;
           expect(addAdjacentStatementsSpy.calls.first().args[2])
-              .toContain(`/*@__PURE__*/ ɵngcc0.setClassMetadata(`);
+              .toContain(`/*@__PURE__*/ (function () { ɵngcc0.setClassMetadata(`);
           const addImportsSpy = testFormatter.addImports as jasmine.Spy;
           expect(addImportsSpy.calls.first().args[1]).toEqual([
             {specifier: './r3_symbols', qualifier: 'ɵngcc0'}
@@ -588,7 +588,7 @@ UndecoratedBase.ɵdir = ɵngcc0.ɵɵdefineDirective({ type: UndecoratedBase, vie
               decorationAnalyses, switchMarkerAnalyses, privateDeclarationsAnalyses);
           const addAdjacentStatementsSpy = testFormatter.addAdjacentStatements as jasmine.Spy;
           expect(addAdjacentStatementsSpy.calls.first().args[2])
-              .toContain(`/*@__PURE__*/ setClassMetadata(`);
+              .toContain(`/*@__PURE__*/ (function () { setClassMetadata(`);
           const addImportsSpy = testFormatter.addImports as jasmine.Spy;
           expect(addImportsSpy.calls.first().args[1]).toEqual([]);
         });

packages/compiler-cli/src/ngtsc/annotations/src/metadata.ts

@@ -6,7 +6,7 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {Expression, ExternalExpr, FunctionExpr, Identifiers, InvokeFunctionExpr, LiteralArrayExpr, LiteralExpr, ReturnStatement, Statement, WrappedNodeExpr, literalMap} from '@angular/compiler';
+import {Expression, ExternalExpr, FunctionExpr, Identifiers, InvokeFunctionExpr, LiteralArrayExpr, LiteralExpr, NONE_TYPE, ReturnStatement, Statement, WrappedNodeExpr, literalMap} from '@angular/compiler';
 import * as ts from 'typescript';
 
 import {DefaultImportRecorder} from '../../imports';
@@ -84,11 +84,15 @@ export function generateSetClassMetadataCall(
         new WrappedNodeExpr(metaDecorators),
         metaCtorParameters,
         new WrappedNodeExpr(metaPropDecorators),
-      ],
+      ]);
+  const iifeFn = new FunctionExpr([], [fnCall.toStmt()], NONE_TYPE);
+  const iife = new InvokeFunctionExpr(
+      /* fn */ iifeFn,
+      /* args */[],
       /* type */ undefined,
       /* sourceSpan */ undefined,
       /* pure */ true);
-  return fnCall.toStmt();
+  return iife.toStmt();
 }
 
 /**

packages/compiler-cli/src/ngtsc/annotations/test/metadata_spec.ts

@@ -23,7 +23,7 @@ runInEachFileSystem(() => {
     @Component('metadata') class Target {}
     `);
       expect(res).toEqual(
-          `/*@__PURE__*/ i0.ɵsetClassMetadata(Target, [{ type: Component, args: ['metadata'] }], null, null);`);
+          `/*@__PURE__*/ (function () { i0.ɵsetClassMetadata(Target, [{ type: Component, args: ['metadata'] }], null, null); })();`);
     });
 
     it('should convert namespaced decorated class metadata', () => {
@@ -33,7 +33,7 @@ runInEachFileSystem(() => {
     @core.Component('metadata') class Target {}
     `);
       expect(res).toEqual(
-          `/*@__PURE__*/ i0.ɵsetClassMetadata(Target, [{ type: core.Component, args: ['metadata'] }], null, null);`);
+          `/*@__PURE__*/ (function () { i0.ɵsetClassMetadata(Target, [{ type: core.Component, args: ['metadata'] }], null, null); })();`);
     });
 
     it('should convert decorated class constructor parameter metadata', () => {

packages/compiler-cli/test/ngtsc/ngtsc_spec.ts

@@ -2853,6 +2853,21 @@ runInEachFileSystem(os => {
          expect(jsContents).toContain('directives: function () { return [CmpB]; }');
        });
 
+    it('should wrap setClassMetadata in an iife', () => {
+      env.write('test.ts', `
+        import {Injectable} from '@angular/core';
+
+        @Injectable({providedIn: 'root'})
+        export class Service {}
+      `);
+
+      env.driveMain();
+      const jsContents = env.getContents('test.js').replace(/\s+/g, ' ');
+      expect(jsContents)
+          .toContain(
+              `/*@__PURE__*/ (function () { i0.ɵsetClassMetadata(Service, [{ type: Injectable, args: [{ providedIn: 'root' }] }], null, null); })();`);
+    });
+
     it('should emit setClassMetadata calls for all types', () => {
       env.write('test.ts', `
       import {Component, Directive, Injectable, NgModule, Pipe} from '@angular/core';

packages/compiler/src/compiler.ts

@@ -78,7 +78,7 @@ export * from './ml_parser/tags';
 export {LexerRange} from './ml_parser/lexer';
 export * from './ml_parser/xml_parser';
 export {NgModuleCompiler} from './ng_module_compiler';
-export {ArrayType, AssertNotNull, DYNAMIC_TYPE, BinaryOperator, BinaryOperatorExpr, BuiltinMethod, BuiltinType, BuiltinTypeName, BuiltinVar, CastExpr, ClassField, ClassMethod, ClassStmt, CommaExpr, CommentStmt, ConditionalExpr, DeclareFunctionStmt, DeclareVarStmt, Expression, ExpressionStatement, ExpressionType, ExpressionVisitor, ExternalExpr, ExternalReference, literalMap, FunctionExpr, IfStmt, InstantiateExpr, InvokeFunctionExpr, InvokeMethodExpr, JSDocCommentStmt, LiteralArrayExpr, LiteralExpr, LiteralMapExpr, MapType, NotExpr, ReadKeyExpr, ReadPropExpr, ReadVarExpr, ReturnStatement, StatementVisitor, ThrowStmt, TryCatchStmt, Type, TypeVisitor, WrappedNodeExpr, WriteKeyExpr, WritePropExpr, WriteVarExpr, StmtModifier, Statement, STRING_TYPE, TypeofExpr, collectExternalReferences} from './output/output_ast';
+export {ArrayType, AssertNotNull, DYNAMIC_TYPE, BinaryOperator, BinaryOperatorExpr, BuiltinMethod, BuiltinType, BuiltinTypeName, BuiltinVar, CastExpr, ClassField, ClassMethod, ClassStmt, CommaExpr, CommentStmt, ConditionalExpr, DeclareFunctionStmt, DeclareVarStmt, Expression, ExpressionStatement, ExpressionType, ExpressionVisitor, ExternalExpr, ExternalReference, literalMap, FunctionExpr, IfStmt, InstantiateExpr, InvokeFunctionExpr, InvokeMethodExpr, JSDocCommentStmt, LiteralArrayExpr, LiteralExpr, LiteralMapExpr, MapType, NotExpr, NONE_TYPE, ReadKeyExpr, ReadPropExpr, ReadVarExpr, ReturnStatement, StatementVisitor, ThrowStmt, TryCatchStmt, Type, TypeVisitor, WrappedNodeExpr, WriteKeyExpr, WritePropExpr, WriteVarExpr, StmtModifier, Statement, STRING_TYPE, TypeofExpr, collectExternalReferences} from './output/output_ast';
 export {EmitterVisitorContext} from './output/abstract_emitter';
 export {JitEvaluator} from './output/output_jit';
 export * from './output/ts_emitter';