optimizing experimentalDecorators feature

Author: Sagi

README.md

@@ -55,12 +55,12 @@ All you need to do is specify the list of extern files after the `externs` optio
 tscc app.ts --module commonjs --externs externs/app-extern.d.ts...
 ```
 
-You can also specify the files in a `ts.config` file.<br/>
-use the `project` option to locate the ts.config file:<br/> 
+You can also specify the files in a `tsconfig.json` file.<br/>
+use the `project` option to locate the tsconfig.json file:<br/> 
 ```js
 tscc --project [project specific directory]
 ```
-and declare the options in the `ts.config` file: 
+and declare the options in the `tsconfig.json` file: 
 ```js
 {
   "compilerOptions": {
@@ -130,6 +130,56 @@ var EventType = {
     mousedown: 1
 };
 ```
+Ignore experimentalDecorators warning message
+
+### experimentalDecorators and ignoreDecoratorsWarning 
+In case you annotate your class/methods/params with decorators without enabling the `experimentalDecorators` option, 
+`TypeScript` will emit all the code that enables this feature, but will output a warning message to enable this option.
+```js
+function f() {
+    console.log("f(): evaluated");
+    return function (target, propertyKey: string, descriptor: PropertyDescriptor) {
+        console.log("f(): called");
+    } 
+}
+
+class C {
+    @f()
+    method() {}
+}
+```
+The output will be:
+>  Experimental support for decorators is a feature that is subject to change in a future release.<br/>
+>  Set the 'experimentalDecorators' option to remove this warning.
+
+`typescript-closure-compiler` changes this behaviour and omits all decorators relevant code when the `experimentalDecorators` is not  enabled, thus ensuring that the generated javascript will not include unnecessary code.<br/>
+In addition `typescript-closure-compiler` enables you to use the `ignoreDecoratorsWarning` option in order to ignore the warning message.<br/>
+These two options enables you to write your code once using decorations, but to omit the decorations related code using configuration, much like choosing the verbosity of a logger using configuration.<br/><br/> 
+A reasonable scenario would be to decorate your class/methods/params with decorators for debug purposes but to omit this code in the final release.<br/>
+All you have to do is create two tsconfig.json files one for debug and one for release.<br/>
+The release file should include the `ignoreDecoratorsWarning`.
+The debug file should include the `experimentalDecorators`.
+
+#### release
+```js
+{
+  "compilerOptions": {
+    "ignoreDecoratorsWarning": true
+  }
+  "files": [
+  ]
+}
+``` 
+#### debug
+```js
+{
+  "compilerOptions": {
+    "experimentalDecorators": true
+  }
+  "files": [
+  ]
+}
+``` 
 
 ### Usage Examples
 
@@ -170,4 +220,4 @@ jake build
 
 ## License
 
-Like the TypeScript compiler itself, this code is licensed under the [Apache License 2.0](http://typescript.codeplex.com/license).
+Like the TypeScript compiler itself, this code is licensed under the [Apache License 2.0](http://typescript.codeplex.com/license).

package.json

@@ -1,7 +1,7 @@
 {
   "name": "typescript-closure-compiler",
   "author": "Sagi Fogel",
-  "version": "1.8.3",
+  "version": "1.8.4",
   "description": "Patches the TypeScript compiler to generate JSDoc annotations",
   "dependencies": {
   },

src/compiler/checker.ts

@@ -47,7 +47,7 @@ namespace ts {
         const emptyArray: any[] = [];
         const emptySymbols: SymbolTable = {};
 
-        const compilerOptions = host.getCompilerOptions();
+        const compilerOptions = <ExtendedCompilerOptions>host.getCompilerOptions();
         const languageVersion = compilerOptions.target || ScriptTarget.ES3;
         const modulekind = getEmitModuleKind(compilerOptions);
         const allowSyntheticDefaultImports = typeof compilerOptions.allowSyntheticDefaultImports !== "undefined" ? compilerOptions.allowSyntheticDefaultImports : modulekind === ModuleKind.System;
@@ -12851,7 +12851,7 @@ namespace ts {
                 return;
             }
 
-            if (!compilerOptions.experimentalDecorators) {
+            if (!compilerOptions.experimentalDecorators && !compilerOptions.ignoreDecoratorsWarning) {
                 error(node, Diagnostics.Experimental_support_for_decorators_is_a_feature_that_is_subject_to_change_in_a_future_release_Set_the_experimentalDecorators_option_to_remove_this_warning);
             }
 

src/compiler/commandLineParser.ts

@@ -333,6 +333,10 @@ namespace ts {
         {
             name: "emitOneSideEnums",
             type: "boolean"
+        },
+        {
+            name: "ignoreDecoratorsWarning",
+            type: "boolean"
         }
     ];
 

src/compiler/emitter.ts

@@ -42,6 +42,7 @@ namespace ts {
         externsOutFile?: string
         emitAnnotations: boolean;
         emitOneSideEnums: boolean;
+        ignoreDecoratorsWarning: boolean;
     }
 
     export interface ExtendedParsedCommandLine extends ParsedCommandLine {
@@ -7540,6 +7541,9 @@ const _super = (function (geti, seti) {
                 if (decoratedClassAlias !== undefined) {
                     write(` = ${decoratedClassAlias}`);
                 }
+                else {
+                    forceWriteLine();
+                }
 
                 write(" = __decorate([");
                 increaseIndent();
@@ -9616,7 +9620,7 @@ const _super = (function (geti, seti) {
                         decorateEmitted = true;
                     }
 
-                    if (!paramEmitted && node.flags & NodeFlags.HasParamDecorators) {
+                    if (compilerOptions.experimentalDecorators && !paramEmitted && node.flags & NodeFlags.HasParamDecorators) {
                         emitParamDecorateAnnotation();
                         writeLines(paramHelper);
                         paramEmitted = true;

typescript.js

@@ -27491,7 +27491,7 @@ ts.createTypeChecker = function (host, produceDiagnostics) {
         if (!ts.nodeCanBeDecorated(node)) {
             return;
         }
-        if (!compilerOptions.experimentalDecorators) {
+        if (!compilerOptions.experimentalDecorators && !compilerOptions.ignoreDecoratorsWarning) {
             error(node, ts.Diagnostics.Experimental_support_for_decorators_is_a_feature_that_is_subject_to_change_in_a_future_release_Set_the_experimentalDecorators_option_to_remove_this_warning);
         }
         if (compilerOptions.emitDecoratorMetadata) {
@@ -41620,7 +41620,7 @@ ts.emitFiles = function (typeChecker, resolver, host, targetSourceFile) {
                     }
                     decorateEmitted = true;
                 }
-                if (!paramEmitted && node.flags & 16777216 /* HasParamDecorators */) {
+                if (compilerOptions.experimentalDecorators && !paramEmitted && node.flags & 16777216 /* HasParamDecorators */) {
                     emitParamDecorateAnnotation();
                     writeLines(paramHelper);
                     paramEmitted = true;
@@ -43720,6 +43720,10 @@ ts.optionDeclarations = [
     {
         name: "emitOneSideEnums",
         type: "boolean"
+    },
+    {
+        name: "ignoreDecoratorsWarning",
+        type: "boolean"
     }
 ];
 /* @internal */