René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"`NG_BUILD_OPTIMIZE_CHUNKS` can cause variable name collisions","articleBody":"### Command\n\nbuild\n\n### Is this a regression?\n\n- [ ] Yes, this behavior used to work in the previous version\n\n### The previous version in which this bug was not present was\n\n_No response_\n\n### Description\n\nYes `NG_BUILD_OPTIMIZE_CHUNKS` is still experimental. This is just a bug I came across while testing it for #27715. I hit a rather nasty edge case with it on where two variable names ended up colliding inside main.js, one from a core Angular package, and the other being one of my components. Thankfully it broke the runtime early on cause otherwise I never would've caught it.\n\nThe mangled variable name that got hit was `Wb`. The first occurrence appears to be from https://github.com/angular/angular/blob/17d8a88ddcce3f850b8ab72252e05720e1f3a8be/packages/core/src/render3/definition.ts#L398-L436\n```js\nfunction Wb(e){return ro$3(()=\u003e({type:e.type,bootstrap:e.bootstrap||ce$4,declarations:e.declarations||ce$4,imports:e.imports||ce$4,exports:e.exports||ce$4,transitiveCompileScopes:null,schemas:e.schemas||null,id:e.id||null}))}\n```\nThe second occurrence comes from one of my components (snippet under reproduction)\n```js\nvar Wb=[`open`,`opening`,`toggle`],Fi=class o{constructor(e,t){this._document=e;this._elementRef=t;let r=Wb.map(i=\u003e$U(ea(this._document,i,{capture:!0,passive:!0}).pipe(Pe$11(s=\u003es.target instanceof Element\u0026\u0026s.target!==this._elementRef.nativeElement\u0026\u0026!s.target.tagName.toLowerCase().startsWith(`md-menu`)))));\n```\n`Wb` breaks upon calling it on the third occurrence \u003cins\u003ein the same line as the previous\u003c/ins\u003e (which I assume means the same chunk), which appears to be from https://github.com/angular/components/blob/main/src/cdk-experimental/scrolling/scrolling-module.ts\n```js\nstatic ɵdir=Qb({type:o,selectors:[[`cdk-virtual-scroll-viewport`,`autosize`,``]],inputs:{minBufferPx:`minBufferPx`,maxBufferPx:`maxBufferPx`},features:[mw([{provide:bi$1,useFactory:D_,deps:[ci$5(()=\u003eo)]}]),TI]})}return o})(),Jh=(()=\u003e{class o{static ɵfac=function(r){return new(r||o)};static ɵmod=Wb({type:o});\n```\n\n### Minimal Reproduction\n\nThe mangled names appear to follow a deterministic sequence so you just have to hit it with enough variable declarations and some luck. Best I can offer is the component that got hit:\n```ts\nimport {\n  ChangeDetectionStrategy,\n  Component,\n  DOCUMENT,\n  ElementRef,\n  Inject,\n} from '@angular/core';\nimport { toSignal } from '@angular/core/rxjs-interop';\nimport { filter, fromEvent } from 'rxjs';\n\nconst POPOVER_EVENTS = ['open', 'opening', 'toggle'];\n\n@Component({\n  selector: 'md-menu',\n  styleUrl: './menu.component.scss',\n  templateUrl: './menu.component.html',\n})\nexport class MenuComponent {\n  constructor(\n    @Inject(DOCUMENT) private readonly _document: Document,\n    private readonly _elementRef: ElementRef\u003cHTMLElement\u003e,\n  ) {\n    const signals = POPOVER_EVENTS.map((name) =\u003e\n      toSignal(\n        fromEvent(this._document, name, { capture: true, passive: true }).pipe(\n          filter(\n            (value) =\u003e\n              value.target instanceof Element \u0026\u0026\n              value.target !== this._elementRef.nativeElement \u0026\u0026\n              !value.target.tagName.toLowerCase().startsWith('md-menu'),\n          ),\n        ),\n      ),\n    );\n  }\n}\n\n```\n\n### Exception or Error\n\n```text\nUncaught TypeError: Wb is not a function\n    at \u003cstatic_initializer\u003e (main-3IQSYYTY.js:1066:5353)\n    at main-3IQSYYTY.js:1066:5278\n    at main-3IQSYYTY.js:1066:5399\n    at main-3IQSYYTY.js:1:101\n    at main-3IQSYYTY.js:1068:36238\n```\n\n### Your Environment\n\n```text\nAngular CLI       : 21.2.2\nAngular           : 21.1.5\nNode.js           : 24.14.0\nPackage Manager   : pnpm 10.32.1\nOperating System  : win32 x64\n```\n\n### Anything else relevant?\n\n_No response_","author":{"url":"https://github.com/austinw-fineart","@type":"Person","name":"austinw-fineart"},"datePublished":"2026-03-13T09:42:41.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":4},"url":"https://github.com/32764/angular-cli/issues/32764"}