error TS1219: Experimental support for decorators is a feature that is subject to change in a future release

Question

In a ASP.NET Core Web Application project can't fix this errors in the latest Visual Studio 2015:

Scripts\app\AppComponent.component.ts(7,14): error TS1219: Experimental support for decorators is a feature that is subject to change in a future release. Set the 'experimentalDecorators' option to remove this warning.
Scripts\app\app.component.ts(7,14): error TS1219: Experimental support for decorators is a feature that is subject to change in a future release. Set the 'experimentalDecorators' option to remove this warning.
Scripts\app\app.module.ts(16,14): error TS1219: Experimental support for decorators is a feature that is subject to change in a future release. Set the 'experimentalDecorators' option to remove this warning.
C:/Users/plato/Documents/Visual Studio 2015/Projects/OpenGameList/src/OpenGameListWebApp/node_modules/@angular/common/src/directives/ng_class.d.ts(46,34): error TS2304: Cannot find name 'Set'.
C:/Users/plato/Documents/Visual Studio 2015/Projects/OpenGameList/src/OpenGameListWebApp/node_modules/@angular/common/src/pipes/async_pipe.d.ts(44,38): error TS2304: Cannot find name 'Promise'.
C:/Users/plato/Documents/Visual Studio 2015/Projects/OpenGameList/src/OpenGameListWebApp/node_modules/@angular/compiler/src/compile_metadata.d.ts(347,20): error TS2304: Cannot find name 'Set'.
C:/Users/plato/Documents/Visual Studio 2015/Projects/OpenGameList/src/OpenGameListWebApp/node_modules/@angular/compiler/src/compile_metadata.d.ts(348,15): error TS2304: Cannot find name 'Set'.
C:/Users/plato/Documents/Visual Studio 2015/Projects/OpenGameList/src/OpenGameListWebApp/node_modules/@angular/compiler/src/directive_normalizer.d.ts(19,100): error TS2304: Cannot find name 'Promise'.
C:/Users/plato/Documents/Visual Studio 2015/Projects/OpenGameList/src/OpenGameListWebApp/node_modules/@angular/compiler/src/directive_normalizer.d.ts(21,74): error TS2304: Cannot find name 'Promise'.
C:/Users/plato/Documents/Visual Studio 2015/Projects/OpenGameList/src/OpenGameListWebApp/node_modules/@angular/compiler/src/offline_compiler.d.ts(15,26): error TS2304: Cannot find name 'Map'.
C:/Users/plato/Documents/Visual Studio 2015/Projects/OpenGameList/src/OpenGameListWebApp/node_modules/@angular/compiler/src/offline_compiler.d.ts(16,38): error TS2304: Cannot find name 'Map'.
C:/Users/plato/Documents/Visual Studio 2015/Projects/OpenGameList/src/OpenGameListWebApp/node_modules/@angular/compiler/src/offline_compiler.d.ts(33,124): error TS2304: Cannot find name 'Promise'.
C:/Users/plato/Documents/Visual Studio 2015/Projects/OpenGameList/src/OpenGameListWebApp/node_modules/@angular/compiler/src/output/output_ast.d.ts(424,63): error TS2304: Cannot find name 'Set'.
C:/Users/plato/Documents/Visual Studio 2015/Projects/OpenGameList/src/OpenGameListWebApp/node_modules/@angular/compiler/src/resource_loader.d.ts(13,23): error TS2304: Cannot find name 'Promise'.
C:/Users/plato/Documents/Visual Studio 2015/Projects/OpenGameList/src/OpenGameListWebApp/node_modules/@angular/compiler/src/runtime_compiler.d.ts(42,49): error TS2304: Cannot find name 'Promise'.
C:/Users/plato/Documents/Visual Studio 2015/Projects/OpenGameList/src/OpenGameListWebApp/node_modules/@angular/compiler/src/runtime_compiler.d.ts(44,65): error TS2304: Cannot find name 'Promise'.
C:/Users/plato/Documents/Visual Studio 2015/Projects/OpenGameList/src/OpenGameListWebApp/node_modules/@angular/compiler/src/template_parser/template_parser.d.ts(45,12): error TS2304: Cannot find name 'Set'.
C:/Users/plato/Documents/Visual Studio 2015/Projects/OpenGameList/src/OpenGameListWebApp/node_modules/@angular/compiler/src/util.d.ts(36,18): error TS2304: Cannot find name 'Promise'.
C:/Users/plato/Documents/Visual Studio 2015/Projects/OpenGameList/src/OpenGameListWebApp/node_modules/@angular/compiler/src/util.d.ts(37,46): error TS2304: Cannot find name 'Promise'.
C:/Users/plato/Documents/Visual Studio 2015/Projects/OpenGameList/src/OpenGameListWebApp/node_modules/@angular/compiler/src/view_compiler/compile_element.d.ts(33,16): error TS2304: Cannot find name 'Map'.
C:/Users/plato/Documents/Visual Studio 2015/Projects/OpenGameList/src/OpenGameListWebApp/node_modules/@angular/compiler/src/view_compiler/compile_query.d.ts(24,49): error TS2304: Cannot find name 'Map'.
C:/Users/plato/Documents/Visual Studio 2015/Projects/OpenGameList/src/OpenGameListWebApp/node_modules/@angular/compiler/src/view_compiler/compile_view.d.ts(29,18): error TS2304: Cannot find name 'Map'.
C:/Users/plato/Documents/Visual Studio 2015/Projects/OpenGameList/src/OpenGameListWebApp/node_modules/@angular/compiler/src/view_compiler/compile_view.d.ts(52,16): error TS2304: Cannot find name 'Map'.
C:/Users/plato/Documents/Visual Studio 2015/Projects/OpenGameList/src/OpenGameListWebApp/node_modules/@angular/compiler/src/view_compiler/compile_view.d.ts(54,13): error TS2304: Cannot find name 'Map'.
C:/Users/plato/Documents/Visual Studio 2015/Projects/OpenGameList/src/OpenGameListWebApp/node_modules/@angular/core/src/application_init.d.ts(16,18): error TS2304: Cannot find name 'Promise'.
C:/Users/plato/Documents/Visual Studio 2015/Projects/OpenGameList/src/OpenGameListWebApp/node_modules/@angular/core/src/application_ref.d.ts(106,67): error TS2304: Cannot find name 'Promise'.
C:/Users/plato/Documents/Visual Studio 2015/Projects/OpenGameList/src/OpenGameListWebApp/node_modules/@angular/core/src/application_ref.d.ts(122,101): error TS2304: Cannot find name 'Promise'.
C:/Users/plato/Documents/Visual Studio 2015/Projects/OpenGameList/src/OpenGameListWebApp/node_modules/@angular/core/src/application_ref.d.ts(148,67): error TS2304: Cannot find name 'Promise'.
C:/Users/plato/Documents/Visual Studio 2015/Projects/OpenGameList/src/OpenGameListWebApp/node_modules/@angular/core/src/application_ref.d.ts(150,101): error TS2304: Cannot find name 'Promise'.
C:/Users/plato/Documents/Visual Studio 2015/Projects/OpenGameList/src/OpenGameListWebApp/node_modules/@angular/core/src/change_detection/differs/default_keyvalue_differ.d.ts(24,15): error TS2304: Cannot find name 'Map'.
C:/Users/plato/Documents/Visual Studio 2015/Projects/OpenGameList/src/OpenGameListWebApp/node_modules/@angular/core/src/change_detection/differs/default_keyvalue_differ.d.ts(28,16): error TS2304: Cannot find name 'Map'.
C:/Users/plato/Documents/Visual Studio 2015/Projects/OpenGameList/src/OpenGameListWebApp/node_modules/@angular/core/src/di/reflective_provider.d.ts(88,123): error TS2304: Cannot find name 'Map'.
C:/Users/plato/Documents/Visual Studio 2015/Projects/OpenGameList/src/OpenGameListWebApp/node_modules/@angular/core/src/di/reflective_provider.d.ts(88,165): error TS2304: Cannot find name 'Map'.
C:/Users/plato/Documents/Visual Studio 2015/Projects/OpenGameList/src/OpenGameListWebApp/node_modules/@angular/core/src/facade/collection.d.ts(4,9): error TS2304: Cannot find name 'Map'.
C:/Users/plato/Documents/Visual Studio 2015/Projects/OpenGameList/src/OpenGameListWebApp/node_modules/@angular/core/src/facade/collection.d.ts(5,30): error TS2304: Cannot find name 'Map'.
C:/Users/plato/Documents/Visual Studio 2015/Projects/OpenGameList/src/OpenGameListWebApp/node_modules/@angular/core/src/facade/collection.d.ts(8,43): error TS2304: Cannot find name 'Map'.
C:/Users/plato/Documents/Visual Studio 2015/Projects/OpenGameList/src/OpenGameListWebApp/node_modules/@angular/core/src/facade/collection.d.ts(10,23): error TS2304: Cannot find name 'Map'.
C:/Users/plato/Documents/Visual Studio 2015/Projects/OpenGameList/src/OpenGameListWebApp/node_modules/@angular/core/src/facade/collection.d.ts(11,25): error TS2304: Cannot find name 'Map'.
C:/Users/plato/Documents/Visual Studio 2015/Projects/OpenGameList/src/OpenGameListWebApp/node_modules/@angular/core/src/facade/lang.d.ts(12,17): error TS2304: Cannot find name 'Map'.
C:/Users/plato/Documents/Visual Studio 2015/Projects/OpenGameList/src/OpenGameListWebApp/node_modules/@angular/core/src/facade/lang.d.ts(13,17): error TS2304: Cannot find name 'Set'.
C:/Users/plato/Documents/Visual Studio 2015/Projects/OpenGameList/src/OpenGameListWebApp/node_modules/@angular/core/src/linker/compiler.d.ts(53,49): error TS2304: Cannot find name 'Promise'.
C:/Users/plato/Documents/Visual Studio 2015/Projects/OpenGameList/src/OpenGameListWebApp/node_modules/@angular/core/src/linker/compiler.d.ts(61,65): error TS2304: Cannot find name 'Promise'.
C:/Users/plato/Documents/Visual Studio 2015/Projects/OpenGameList/src/OpenGameListWebApp/node_modules/@angular/core/src/linker/ng_module_factory_loader.d.ts(14,34): error TS2304: Cannot find name 'Promise'.
C:/Users/plato/Documents/Visual Studio 2015/Projects/OpenGameList/src/OpenGameListWebApp/node_modules/@angular/core/src/linker/system_js_ng_module_factory_loader.d.ts(28,25): error TS2304: Cannot find name 'Promise'.
C:/Users/plato/Documents/Visual Studio 2015/Projects/OpenGameList/src/OpenGameListWebApp/node_modules/@angular/core/src/util/lang.d.ts(8,53): error TS2304: Cannot find name 'Promise'.
C:/Users/plato/Documents/Visual Studio 2015/Projects/OpenGameList/src/OpenGameListWebApp/node_modules/@angular/http/src/headers.d.ts(45,59): error TS2304: Cannot find name 'Map'.
C:/Users/plato/Documents/Visual Studio 2015/Projects/OpenGameList/src/OpenGameListWebApp/node_modules/@angular/http/src/url_search_params.d.ts(46,16): error TS2304: Cannot find name 'Map'.
C:/Users/plato/Documents/Visual Studio 2015/Projects/OpenGameList/src/OpenGameListWebApp/node_modules/@angular/platform-browser-dynamic/src/resource_loader/resource_loader_impl.d.ts(10,23): error TS2304: Cannot find name 'Promise'.
C:/Users/plato/Documents/Visual Studio 2015/Projects/OpenGameList/src/OpenGameListWebApp/node_modules/@angular/platform-browser/src/browser/browser_adapter.d.ts(79,33): error TS2304: Cannot find name 'Map'.
C:/Users/plato/Documents/Visual Studio 2015/Projects/OpenGameList/src/OpenGameListWebApp/node_modules/@angular/platform-browser/src/dom/dom_adapter.d.ts(97,42): error TS2304: Cannot find name 'Map'.
C:/Users/plato/Documents/Visual Studio 2015/Projects/OpenGameList/src/OpenGameListWebApp/node_modules/@angular/platform-browser/src/dom/dom_renderer.d.ts(18,37): error TS2304: Cannot find name 'Map'.
C:/Users/plato/Documents/Visual Studio 2015/Projects/OpenGameList/src/OpenGameListWebApp/node_modules/@angular/platform-browser/src/facade/collection.d.ts(4,9): error TS2304: Cannot find name 'Map'.
C:/Users/plato/Documents/Visual Studio 2015/Projects/OpenGameList/src/OpenGameListWebApp/node_modules/@angular/platform-browser/src/facade/collection.d.ts(5,30): error TS2304: Cannot find name 'Map'.
C:/Users/plato/Documents/Visual Studio 2015/Projects/OpenGameList/src/OpenGameListWebApp/node_modules/@angular/platform-browser/src/facade/collection.d.ts(8,43): error TS2304: Cannot find name 'Map'.
C:/Users/plato/Documents/Visual Studio 2015/Projects/OpenGameList/src/OpenGameListWebApp/node_modules/@angular/platform-browser/src/facade/collection.d.ts(10,23): error TS2304: Cannot find name 'Map'.
C:/Users/plato/Documents/Visual Studio 2015/Projects/OpenGameList/src/OpenGameListWebApp/node_modules/@angular/platform-browser/src/facade/collection.d.ts(11,25): error TS2304: Cannot find name 'Map'.
C:/Users/plato/Documents/Visual Studio 2015/Projects/OpenGameList/src/OpenGameListWebApp/node_modules/rxjs/Observable.d.ts(10,66): error TS2304: Cannot find name 'Promise'.
C:/Users/plato/Documents/Visual Studio 2015/Projects/OpenGameList/src/OpenGameListWebApp/node_modules/rxjs/Observable.d.ts(66,60): error TS2304: Cannot find name 'Promise'.
C:/Users/plato/Documents/Visual Studio 2015/Projects/OpenGameList/src/OpenGameListWebApp/node_modules/rxjs/Observable.d.ts(66,70): error TS2304: Cannot find name 'Promise'.
C:/Users/plato/Documents/Visual Studio 2015/Projects/OpenGameList/src/OpenGameListWebApp/node_modules/rxjs/observable/PromiseObservable.d.ts(40,31): error TS2304: Cannot find name 'Promise'.
C:/Users/plato/Documents/Visual Studio 2015/Projects/OpenGameList/src/OpenGameListWebApp/node_modules/rxjs/observable/PromiseObservable.d.ts(41,26): error TS2304: Cannot find name 'Promise'.
C:/Users/plato/Documents/Visual Studio 2015/Projects/OpenGameList/src/OpenGameListWebApp/node_modules/rxjs/operator/toPromise.d.ts(7,59): error TS2304: Cannot find name 'Promise'.
C:/Users/plato/Documents/Visual Studio 2015/Projects/OpenGameList/src/OpenGameListWebApp/node_modules/rxjs/operator/toPromise.d.ts(7,69): error TS2304: Cannot find name 'Promise'.
C:/Users/plato/Documents/Visual Studio 2015/Projects/OpenGameList/src/OpenGameListWebApp/node_modules/rxjs/operator/toPromise.d.ts(9,9): error TS2304: Cannot find name 'Promise'.
C:/Users/plato/Documents/Visual Studio 2015/Projects/OpenGameList/src/OpenGameListWebApp/node_modules/rxjs/operator/toPromise.d.ts(10,26): error TS2304: Cannot find name 'Promise'.
C:/Users/plato/Documents/Visual Studio 2015/Projects/OpenGameList/src/OpenGameListWebApp/node_modules/rxjs/operator/toPromise.d.ts(10,36): error TS2304: Cannot find name 'Promise'.

Solution Explorer:

My tsconfig.json:

{
  "compileOnSave": false,
  "compilerOptions": {
    "emitDecoratorMetadata": true,
    "experimentalDecorators": true,
    "module": "system",
    "moduleResolution": "node",
    "noImplicitAny": false,
    "noEmitOnError": false,
    "removeComments": false,
    "target": "es5"
  },
  "exclude": [
    "node_modules",
    "wwwroot"
  ],
  "typeRoots": ["./node_modules/@types"],
  "type": ["core-js"]
}

My package.json:

{
  "version": "1.0.0",
  "name": "opengamelistwebapp",
  "private": true,
  "dependencies": {
    "@angular/common": "2.0.2",
    "@angular/compiler": "2.0.2",
    "@angular/core": "2.0.2",
    "@angular/http": "2.0.2",
    "@angular/platform-browser": "2.0.2",
    "@angular/platform-browser-dynamic": "2.0.2",
    "@angular/upgrade": "2.0.2",
    "core-js": "^2.5.3",
    "reflect-metadata": "^0.1.10",
    "rxjs": "5.0.0-beta.12",
    "systemjs": "^0.20.19",
    "zone.js": "^0.6.21",
    "@types/core-js": "^0.9.44"
  },
  "devDependencies": {
    "gulp": "^3.9.1",
    "gulp-clean": "^0.3.2",
    "gulp-concat": "^2.6.0",
    "gulp-sourcemaps": "^1.6.0",
    "gulp-typescript": "^2.13.6",
    "gulp-uglify": "^2.0.0",
    "typescript": "^2.6.2"
  }
}

My gulpfile.js:

/*
This file in the main entry point for defining Gulp tasks and using Gulp plugins.
Click here to learn more. http://go.microsoft.com/fwlink/?LinkId=518007
*/

var gulp = require("gulp"),
    gp_clean = require("gulp-clean"),
    gp_concat = require("gulp-concat"),
    gp_sourcemaps = require("gulp-sourcemaps"),
    gp_typescript = require("gulp-typescript"),
    gp_uglify = require("gulp-uglify");

var srcPaths = {
    app: ["Scripts/app/main.ts", "Scripts/app/**/*.ts"],
    js: [
        "Scripts/js/**/*js",
        "node_modules/core-js/client/shim.min.js",
        "node_modules/zone.js/dist/zone.js",
        "node_modules/reflect-metadata/Reflect.js",
        "node_modules/systemjs/dist/system.src.js",
        "node_modules/typescript/lib/typescript.js"
    ],
    js_angular: [
        "node_modules/@angular/**"
    ],
    js_rxjs: [
        "node_modules/rxjs/**"
    ]
};

var destPaths = {
    app: "wwwroot/app/",
    js: "wwwroot/js",
    js_angular: "wwwroot/js/@angular/",
    js_rxjs: "wwwroot/js/rxjs/"
};

// Compile, minify and create sourcemaps all TypeScript files and place them to wwwroot/app, together with their js.map files.
gulp.task("app",
    ["app_clean"],
    function() {
        return gulp.src(srcPaths.app)
            .pipe(gp_sourcemaps.init())
            .pipe(gp_typescript(require("./tsconfig.json").compileOptions))
            .pipe(gp_uglify({
                mangle: false
            }))
            .pipe(gp_sourcemaps.write("/"))
            .pipe(gulp.dest(destPaths.app));
    });

// Delete wwwroot/app contents
gulp.task("app_clean",
    function() {
        return gulp.src(destPaths.app + "*", { read: false })
            .pipe(gp_clean({ force: true }));
    });

// Copy all JS files from extrenal libraries to wwwroot/js
gulp.task("js",
    function() {
        gulp.src(srcPaths.js_angular).pipe(gulp.dest(destPaths.js_angular));
        gulp.src(srcPaths.js_rxjs).pipe(gulp.dest(destPaths.js_rxjs));
        return gulp.src(srcPaths.js)
            .pipe(gulp.dest(destPaths.js));
    });

// Delete wwwroot/js contents
gulp.task("js_clean",
    function() {
        return gulp.src(destPaths.js + "*", { read: false })
            .pipe(gp_clean({ force: true }));
    });

// Watch specified files and define what to do upon file changes
gulp.task("watch",
    function() {
        gulp.watch([srcPaths.app, srcPaths.js], ["app", "js"]);
    });

// Global cleanup task
gulp.task("cleanup", ["app_clean", "js_clean"]);
// For Gulp 4
//gulp.task("cleanup", gulp.series("app_clean", "js_clean"));

// Default task
gulp.task("default", ["app", "js", "watch"]);
// For Gulp 4
//gulp.task("default", gulp.series("app", "js", "watch"));

Answer 1

Check if the tsconfig.json file has build in Properties set to "Content" rather than "None", if not right click on the tsconfig file and set the build action to Content. After this reload the project, the error should go away