Sam Wight samwightt
samwightt
/ missing-done-callback-in-subscribe.yml
Last active
September 8, 2025 18:42
ast-grep rule for when you're missing a `done` callback in an observable's `subscribe`. Only triggers when there are assertions inside the subscribe as we don't want to be too hasty.
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| language: TypeScript | |
| id: missing-done-callback-in-subscribe | |
| message: When subscribing to an observable inside a test function, you must call the 'done' function. Otherwise the assertions will never run. | |
| severity: error | |
| note: | | |
| When testing observables in Jest, you must call the `done()` function in the subscribe callback. Jest provides a `done` function to test functions that must be executed to let Jest know when the test is done. | |
| If you don't call the done function, the assertions will never run because Jest will finish the test before the subscribe callback is called. | |
| If possible, it is encouraged to use `firstValueFrom` or `lastValueFrom` instead of subscribing to an observable directly in a test function. These handle subscribing / unsubscribing for you. |
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