angular / angular/angular-cli

Esbuild Web Worker Type Safety and Redundant tsconfig.worker.json

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#30,676 1 comment 0 reactions 0 assignees View on GitHub
angular/build:application area: @angular/build freq1: low severity1: confusing type: bug/fix
Dominant language
TypeScript
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Description

### Command

build

### Is this a regression?

- [ ] Yes, this behavior used to work in the previous version

### The previous version in which this bug was not present was

_No response_

### Description

When using esbuild as the bundler for Angular projects, the support for web workers appears misleading in terms of type safety:

- In the previous webpack-based build setup, web workers had proper TypeScript type checking at build time.

- Currently, esbuild does not type-check web workers during build time. This is not documented or clearly communicated, leading to a false sense of correctness.

- Additionally, creating a project with a web worker generates a `tsconfig.worker.json`, which seems redundant because esbuild doesn't use it for type-checking. Also `builder` contains the `webWorkerTsConfig` option in the schema, as I understand it, this doesn't affect anything. This can confuse developers into thinking their web worker code is properly validated.

**Expected Behavior**

Either esbuild-based builder should perform type checking on web worker files, or there should be clear documentation and/or warnings that type-checking is not performed on workers.

**Current Behavior**

- No build-time type checking for worker code.

- Misleading tsconfig.worker.json is generated, giving false confidence in type safety.

### Minimal Reproduction

1. Generate a new Angular project with esbuild (Angular CLI 18+).
2. Add a web worker via ng generate web-worker.
3. Introduce a type error in the worker file.
4. Run ng build – no type error is reported.

### Exception or Error

```text

```

### Your Environment

```text
Any version with esbuild bundler.
```

### Anything else relevant?

_No response_

Contributor guide

Open the contributing guide

Research direction

Start by reproducing the described Angular CLI esbuild workflow: generate a web worker, add a type error, and run ng build. Inspect the generated tsconfig.worker.json and the builder schema's webWorkerTsConfig option. Done means worker type-checking behavior is corrected or clearly documented, with misleading configuration addressed.

Written by the indexing model from the issue text.

Assessment

Tech stack
angular, typescript
Domain
build-system, cli
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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