ES6 Builds Broken by #6a5aec8

[godenji]

Bug Report

Ionic Info

Ionic:

   ionic (Ionic CLI)             : 4.2.1
   Ionic Framework               : @ionic/angular 4.0.0-beta.13
   @angular-devkit/build-angular : 0.7.5
   @angular-devkit/schematics    : 0.7.5
   @angular/cli                  : 6.2.5
   @ionic/angular-toolkit        : 1.0.0

Cordova:

   cordova (Cordova CLI) : 8.1.2 (cordova-lib@8.1.1)
   Cordova Platforms     : android 7.1.1
   Cordova Plugins       : cordova-plugin-ionic-keyboard 2.1.2, cordova-plugin-ionic-webview 2.0.3, (and 8 other plugins)

System:

   NodeJS : v10.10.0 (/usr/bin/node)
   npm    : 6.4.1
   OS     : Linux 4.16

Describe the Bug
Commit #6a5aec8 breaks ES6 targeted builds.

Steps to Reproduce
Steps to reproduce the behavior:

1. Upgrade to v4 beta 13
2. Set tsconfig.json compile target to es6
3. run ionic serve

Expected Behavior
ES6 targeted builds are produced successfuly.

Additional Context

TypeError: "class constructors must be invoked with |new|"
	BackButtonEmitter http://localhost:8100/vendor.js:129680:35
	Platform http://localhost:8100/vendor.js:129695:27
	_createClass http://localhost:8100/vendor.js:63003:20
	_createProviderInstance http://localhost:8100/vendor.js:62970:26
	resolveNgModuleDep http://localhost:8100/vendor.js:62915:21
	get http://localhost:8100/vendor.js:64022:16
	inject http://localhost:8100/vendor.js:54331:16
	injectArgs http://localhost:8100/vendor.js:54371:23
	convertInjectableProviderToFactory http://localhost:8100/vendor.js:54440:34
	_callFactory http://localhost:8100/vendor.js:63030:20
	_createProviderInstance http://localhost:8100/vendor.js:62973:26
	resolveNgModuleDep http://localhost:8100/vendor.js:62932:17
	_callFactory http://localhost:8100/vendor.js:63036:106
	_createProviderInstance http://localhost:8100/vendor.js:62973:26
	initNgModule http://localhost:8100/vendor.js:62876:32
	NgModuleRef_ http://localhost:8100/vendor.js:64005:9
	createNgModuleRef http://localhost:8100/vendor.js:63988:12
	debugCreateNgModuleRef http://localhost:8100/vendor.js:66419:12
	create http://localhost:8100/vendor.js:67513:16
	bootstrapModuleFactory http://localhost:8100/vendor.js:57837:49
	invoke http://localhost:8100/polyfills.js:2710:17
	onInvoke http://localhost:8100/vendor.js:57262:24
	invoke http://localhost:8100/polyfills.js:2709:17
	run http://localhost:8100/polyfills.js:2460:24
	run http://localhost:8100/vendor.js:57149:54
	bootstrapModuleFactory http://localhost:8100/vendor.js:57833:16
	bootstrapModule http://localhost:8100/vendor.js:57884:38
	invoke http://localhost:8100/polyfills.js:2710:17
	run http://localhost:8100/polyfills.js:2460:24
	scheduleResolveOrReject http://localhost:8100/polyfills.js:3194:29
	invokeTask http://localhost:8100/polyfills.js:2743:17
	runTask http://localhost:8100/polyfills.js:2510:28
	drainMicroTaskQueue http://localhost:8100/polyfills.js:2917:25

Generated JS looks like:

var BackButtonEmitter = /** @class */ (function (_super) {
    __extends(BackButtonEmitter, _super);
    function BackButtonEmitter() {
        return _super !== null && _super.apply(this, arguments) || this;
    }
    BackButtonEmitter.prototype.subscribeWithPriority = function (priority, callback) {
        return this.subscribe(function (ev) {
            ev.register(priority, callback);
        });
    };
    return BackButtonEmitter;
}(_angular_core__WEBPACK_IMPORTED_MODULE_0__["EventEmitter"]));

and build blows up with "class constructors must be invoked with |new|" on this call: _super.apply(this, arguments).

[mhartington]

For reference, this is the commit in question.

6a5aec8

@manucorporat any thoughts on this?

[hal1984]

Same problem

[sanja-h]

Still the same problem with @ionic/angular@4.0.0-beta.15-0.

[godenji]

Still the same problem with @ionic/angular@4.0.0-beta.15-0

That's because the author of the commit that introduced the regression is clearly working on other, presumably more important, issues :)

A quick and dirty hack that "fixes" the issue (i.e. reverts to old behavior) is to change line 32 of node_modules/@ionic/angular/dist/providers/platform.js from
this.backButton = new BackButtonEmitter(); to this.backButton = new EventEmitter();

[ChrisPearce]

Thank you for the fix.

Is the v4.0.0-beta.16 release scheduled to happen soon? It would be very helpful for users whose codebases are ES6 based to use this as soon as possible.

[paulstelzer]

@ChrisPearce Just fork this repository and build it - so you always get the newest version and do not have to wait until the next beta ;)

[paulstelzer]

@manucorporat This issue is still available in beta.16. Your fix is not working. The error is now: "TypeError: Class constructor EventEmitter cannot be invoked without 'new'"

[ChrisPearce]

Is ES6/ES2015 a supported scenario for Ionic v4, or should we only be targeting ES5?

Also, is it intended to support ES2016 and ES2017 (when a mobile device supports these)?

[godenji]

Is ES6/ES2015 a supported scenario for Ionic v4, or should we only be targeting ES5?

I don't see why not, the issue is isolated to a specific area of the code base -- fix is likely trivial.

[manucorporat]

damn.

We are working in a new test app for angular and a CI that runs it in all different browsers to make sure we don't have this kind of issues anymore, thanks you all for the patience!

Reopening issue

[paulstelzer]

Can confirm. es6 build is now possible :)

[ionitron-bot]

Thanks for the issue! This issue is being locked to prevent comments that are not relevant to the original issue. If this is still an issue with the latest version of Ionic, please create a new issue and ensure the template is fully filled out.