feat(compiler): Added support for conditional expressions. (#10366)

Expression evaluated by the static reflector can now supports
conditional expressions.

Closes: #10365

modules/@angular/compiler-cli/src/static_reflector.ts

@@ -307,6 +307,7 @@ export class StaticReflector implements ReflectorReader {
               throw new Error('Recursion not supported');
             }
             calling.set(functionSymbol, true);
+            try {
               let value = targetFunction['value'];
               if (value && (depth != 0 || value.__symbolic != 'error')) {
                 // Determine the arguments
@@ -326,9 +327,11 @@ export class StaticReflector implements ReflectorReader {
                 }
                 return result;
               }
+            } finally {
               calling.delete(functionSymbol);
             }
           }
+        }
 
         if (depth === 0) {
           // If depth is 0 we are evaluating the top level expression that is describing element
@@ -417,6 +420,10 @@ export class StaticReflector implements ReflectorReader {
                     return left % right;
                 }
                 return null;
+              case 'if':
+                let condition = simplify(expression['condition']);
+                return condition ? simplify(expression['thenExpression']) :
+                                   simplify(expression['elseExpression']);
               case 'pre':
                 let operand = simplify(expression['operand']);
                 if (shouldIgnore(operand)) return operand;

modules/@angular/compiler-cli/test/static_reflector_spec.ts

@@ -411,6 +411,16 @@ describe('StaticReflector', () => {
     expect(annotations.length).toBe(1);
     expect(annotations[0].providers).toEqual([{provider: 'a', useValue: 'Some string'}]);
   });
+
+  it('should be able to get the metadata for a class calling a method with a conditional expression',
+     () => {
+       const annotations = reflector.annotations(
+           host.getStaticSymbol('/tmp/src/static-method-call.ts', 'MyCondComponent'));
+       expect(annotations.length).toBe(1);
+       expect(annotations[0].providers).toEqual([
+         [{provider: 'a', useValue: '1'}], [{provider: 'a', useValue: '2'}]
+       ]);
+     });
 });
 
 class MockReflectorHost implements StaticReflectorHost {
@@ -960,6 +970,9 @@ class MockReflectorHost implements StaticReflectorHost {
           static with(data: any) {
             return { provider: 'a', useValue: data }
           }
+          static condMethod(cond: boolean) {
+            return [{ provider: 'a', useValue: cond ? '1' : '2'}];
+          }
         }
       `,
       '/tmp/src/static-method-call.ts': `
@@ -970,6 +983,11 @@ class MockReflectorHost implements StaticReflectorHost {
           providers: MyModule.with(100)
         })
         export class MyComponent { }
+
+        @Component({
+          providers: [MyModule.condMethod(true), MyModule.condMethod(false)]
+        })
+        export class MyCondComponent { }
       `,
       '/tmp/src/static-field.ts': `
         import {Injectable} from 'angular2/core';

tools/@angular/tsc-wrapped/src/evaluator.ts

@@ -511,6 +511,15 @@ export class Evaluator {
           };
         }
         break;
+      case ts.SyntaxKind.ConditionalExpression:
+        const conditionalExpression = <ts.ConditionalExpression>node;
+        const condition = this.evaluateNode(conditionalExpression.condition);
+        const thenExpression = this.evaluateNode(conditionalExpression.whenTrue);
+        const elseExpression = this.evaluateNode(conditionalExpression.whenFalse);
+        if (isPrimitive(condition)) {
+          return condition ? thenExpression : elseExpression;
+        }
+        return {__symbolic: 'if', condition, thenExpression, elseExpression};
       case ts.SyntaxKind.FunctionExpression:
       case ts.SyntaxKind.ArrowFunction:
         return errorSymbol('Function call not supported', node);

tools/@angular/tsc-wrapped/src/schema.ts

@@ -79,7 +79,7 @@ export interface MetadataObject { [name: string]: MetadataValue; }
 export interface MetadataArray { [name: number]: MetadataValue; }
 
 export interface MetadataSymbolicExpression {
-  __symbolic: 'binary'|'call'|'index'|'new'|'pre'|'reference'|'select'|'spread'
+  __symbolic: 'binary'|'call'|'index'|'new'|'pre'|'reference'|'select'|'spread'|'if'
 }
 export function isMetadataSymbolicExpression(value: any): value is MetadataSymbolicExpression {
   if (value) {
@@ -92,6 +92,7 @@ export function isMetadataSymbolicExpression(value: any): value is MetadataSymbo
       case 'reference':
       case 'select':
       case 'spread':
+      case 'if':
         return true;
     }
   }
@@ -140,6 +141,16 @@ export function isMetadataSymbolicPrefixExpression(value: any):
   return value && value.__symbolic === 'pre';
 }
 
+export interface MetadataSymbolicIfExpression extends MetadataSymbolicExpression {
+  __symbolic: 'if';
+  condition: MetadataValue;
+  thenExpression: MetadataValue;
+  elseExpression: MetadataValue;
+}
+export function isMetadataSymbolicIfExpression(value: any): value is MetadataSymbolicIfExpression {
+  return value && value.__symbolic === 'if';
+}
+
 export interface MetadataGlobalReferenceExpression extends MetadataSymbolicExpression {
   __symbolic: 'reference';
   name: string;

tools/@angular/tsc-wrapped/test/collector.spec.ts

@@ -14,10 +14,20 @@ describe('Collector', () => {
 
   beforeEach(() => {
     host = new Host(FILES, [
-      '/app/app.component.ts', '/app/cases-data.ts', '/app/error-cases.ts', '/promise.ts',
-      '/unsupported-1.ts', '/unsupported-2.ts', 'import-star.ts', 'exported-functions.ts',
-      'exported-enum.ts', 'exported-consts.ts', 'static-method.ts', 'static-method-call.ts',
-      'static-field-reference.ts'
+      '/app/app.component.ts',
+      '/app/cases-data.ts',
+      '/app/error-cases.ts',
+      '/promise.ts',
+      '/unsupported-1.ts',
+      '/unsupported-2.ts',
+      'import-star.ts',
+      'exported-functions.ts',
+      'exported-enum.ts',
+      'exported-consts.ts',
+      'static-field-reference.ts',
+      'static-method.ts',
+      'static-method-call.ts',
+      'static-method-with-if.ts',
     ]);
     service = ts.createLanguageService(host, documentRegistry);
     program = service.getProgram();
@@ -410,6 +420,31 @@ describe('Collector', () => {
       }]
     }]);
   });
+
+  it('should be able to collect a method with a conditional expression', () => {
+    let source = program.getSourceFile('/static-method-with-if.ts');
+    let metadata = collector.getMetadata(source);
+    expect(metadata).toBeDefined();
+    let classData = <ClassMetadata>metadata.metadata['MyModule'];
+    expect(classData).toBeDefined();
+    expect(classData.statics).toEqual({
+      with: {
+        __symbolic: 'function',
+        parameters: ['cond'],
+        value: [
+          {__symbolic: 'reference', name: 'MyModule'}, {
+            provider: 'a',
+            useValue: {
+              __symbolic: 'if',
+              condition: {__symbolic: 'reference', name: 'cond'},
+              thenExpression: '1',
+              elseExpression: '2'
+            }
+          }
+        ]
+      }
+    });
+  });
 });
 
 // TODO: Do not use \` in a template literal as it confuses clang-format
@@ -691,6 +726,19 @@ const FILES: Directory = {
     })
     export class Foo { }
   `,
+  'static-method-with-if.ts': `
+    import {Injectable} from 'angular2/core';
+
+    @Injectable()
+    export class MyModule {
+      static with(cond: boolean): any[] {
+        return [
+          MyModule,
+          { provider: 'a', useValue: cond ? '1' : '2' }
+        ];
+      }
+    }
+  `,
   'node_modules': {
     'angular2': {
       'core.d.ts': `