No __PURE_ for component

[WiseBird]

Bug Report or Feature Request (mark with an x)

- [x] bug report -> please search issues before submitting
- [ ] feature request

Area

- [x] devkit
- [ ] schematics

Versions

node - v7.6.0
npm - 4.1.2
ts - 2.5.3
angular - 4.4.5
devkit - 0.0.27

Repro steps

I have a loader that uses build optimizer:

const BuildOptimizer = require('@angular-devkit/build-optimizer').buildOptimizer;

module.exports = function (source) {
    let result = BuildOptimizer({
        content: source,
        emitSourceMap: true,
    });

    return result.content || source;
};

and a simple component:

import {Component} from '@angular/core';

enum Modes { Option1, Option2 }

@Component({
               selector: 'app-root',
               templateUrl: './app.component.html',
           })
export class AppComponent  {
    title = 'app component!';
    mode: Modes;
}

When built it result in

var __decorate = /*@__PURE__*/ __webpack_require__(0).__decorate;
Object.defineProperty(exports, "__esModule", { value: true });
var core_1 = __webpack_require__(2);
var Modes = /*@__PURE__*/ (function () {
    var Modes = {};
    Modes[Modes["Option1"] = 0] = "Option1";
    Modes[Modes["Option2"] = 1] = "Option2";
    return Modes;
})();
var AppComponent = (function () {
    function AppComponent() {
        this.title = 'app component!';
    }
    AppComponent = __decorate([
        core_1.Component({
            selector: 'app-root',
            template: __webpack_require__(47),
        })
    ], AppComponent);
    return AppComponent;
}());
exports.AppComponent = AppComponent;

Repo: https://github.com/WiseBird/ng_devkit_test

Desired functionality

If I understand correctly comopnent class should also be marked as pure: var AppComponent = /*@__PURE__*/ (function () {

[filipesilva]

It should, yes. Thank you for the report and repro. Will investigate.

[filipesilva]

Ok I know what's going on. The transform that adds that pure comment is prefix-functions.

But we only apply it to libraries we know are safe: https://github.com/angular/devkit/blob/master/packages/angular_devkit/build_optimizer/src/build-optimizer/build-optimizer.ts#L80-L92

So your user code does not get it. Perhaps we should have a flag to force it...

[clydin]

Something else to note is that the annotation is only relevant if the component is never used within the application.

[hansl]

@clydin @filipesilva Was this fixed by my fix from yesterday?

[filipesilva]

@hansl no, this is different. It needs a forced flag. I'm putting up a PR for it soon.