fix(observable): add explicit extensions to relative ESM imports by odinr · Pull Request #5307 · equinor/fusion-framework

odinr · 2026-08-16T20:08:06Z

Why is this change needed?
@equinor/fusion-observable's relative import/export specifiers (e.g. ./operators, ../types) had no file extensions. The package's tsconfig inherits moduleResolution: "bundler" from the repo root, so tsc never rewrote these to .js//index.js in the compiled ESM output. That's fine for bundler-based consumers (Vite/webpack), but breaks strict Node.js ESM resolution for any consumer that resolves the published dist/esm output directly (e.g. Vitest running without a bundler), producing module-not-found errors. A downstream consumer had already worked around this with a yarn patch.

What is the current behavior?
Compiled dist/esm/*.js files import sibling modules without extensions (from './operators'), which fails to resolve under strict Node ESM.

What is the new behavior?
Every relative import/export in src/**/*.ts now has an explicit .js (file) or /index.js (directory) extension, so the compiled output resolves correctly under both bundler and strict Node ESM resolution. The package's own tsconfig.json now overrides module/moduleResolution to nodenext so tsc enforces explicit extensions going forward instead of silently allowing them to be omitted again.

What is the intended behavior or invariant?
@equinor/fusion-observable's published ESM output must be resolvable by both bundler-based and non-bundler (native Node ESM) consumers. The package-local nodenext override only affects how this package type-checks its own imports; it does not change how other packages (still on moduleResolution: "bundler") consume this package's emitted .d.ts/.js output.

Does this PR introduce a breaking change?
No. Output paths and public API are unchanged; only the internal module specifiers gained explicit extensions.

Impact assessment:

Breaking changes: No
Version bump: Patch (changeset included)
Consumer impact: Fixes resolution for consumers that load the package's ESM output directly (without a bundler), e.g. Vitest/Node-based tooling.
Downstream impact: Verified other in-repo consumers (e.g. packages/react/app, packages/modules/*, packages/dev-portal) still build cleanly via tsc -b since they still use moduleResolution: "bundler" and consume the emitted declaration/JS files, not the source.

Review guidance:
Diff is mechanical (adding extensions) across ~30 files in packages/utils/observable/src; the interesting parts are tsconfig.json (the nodenext override) and FlowSubject.ts as a representative example. Verified: tsc -b --force, vitest run (42/42 tests), biome check, and fusion-lint all pass; a downstream project-reference build (packages/react/app) also builds clean.

Additional context
The two dead test files under src/__tests__/ (Query.test.ts, ReactiveObservable.test.ts) reference modules that no longer exist and are excluded from both this package's tsconfig.json and its vitest.config.ts (test.include: ['tests/**']); they were intentionally left untouched as out of scope.

Related issues
None.

Checklist

Confirm completion of the self-review checklist
Confirm TSDoc captures intent for functions, hooks, components, classes, and named arrow functions (no TSDoc content changed)
Confirm iterator blocks, decision gates, RxJS chains, and complex decisions explain why they exist (unchanged)
Confirm React logic and derived values are resolved before markup when applicable (n/a)
Confirm README/docs are updated for user-facing changes (n/a, internal fix)
Confirm changes to target branch validation
- Included files validated
- No new linting warnings
- Not a duplicate PR
Confirm adherence to code of conduct

Relative import/export specifiers in @equinor/fusion-observable's source lacked file extensions (e.g. './operators' instead of './operators/index.js'). Under the package's inherited moduleResolution: bundler tsconfig, tsc never adds them, so the compiled ESM output only resolves for bundler-based consumers. Consumers resolving the published dist directly under strict Node.js ESM (e.g. vitest without a bundler) fail with module-not-found errors. Add explicit .js/.js/index.js extensions to every relative import/export in src, and override the package's own tsconfig to module/moduleResolution: nodenext so tsc enforces this going forward instead of silently regressing.

changeset-bot · 2026-08-16T20:08:11Z

🦋 Changeset detected

Latest commit: bd1fbb7

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 15 packages

Name	Type
@equinor/fusion-observable	Patch
@equinor/fusion-framework-dev-portal	Patch
@equinor/fusion-framework-module-analytics	Patch
@equinor/fusion-framework-module-telemetry	Patch
@equinor/fusion-framework-module-widget	Patch
@equinor/fusion-framework-react-app	Patch
portal-analytics	Patch
@equinor/fusion-framework-cli	Patch
@equinor/fusion-framework-app	Patch
@equinor/fusion-framework	Patch
@equinor/fusion-framework-vite-plugin-spa	Patch
@equinor/fusion-framework-vitest-plugin-react-app	Patch
poc-portal	Patch
portal	Patch
@equinor/fusion-framework-dev-server	Patch

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Pull request overview

Fixes strict Node.js ESM resolution for @equinor/fusion-observable.

Changes:

Adds explicit .js or /index.js extensions to relative module specifiers.
Enables NodeNext resolution to enforce valid ESM imports.
Adds a patch changeset.

Reviewed changes

Copilot reviewed 32 out of 32 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
`.changeset/observable_fix-esm-import-extensions.md`	Documents the ESM resolution fix.
`packages/utils/observable/tsconfig.json`	Enables NodeNext module resolution.
`packages/utils/observable/src/types/reducers.ts`	Adds an explicit import extension.
`packages/utils/observable/src/types/index.ts`	Adds explicit export extensions.
`packages/utils/observable/src/to-observable.ts`	Adds an explicit import extension.
`packages/utils/observable/src/react/useObservableState.ts`	Uses the explicit types entry point.
`packages/utils/observable/src/react/useObservableSelectorState.ts`	Adds explicit relative extensions.
`packages/utils/observable/src/react/useObservableSelector.ts`	Adds explicit relative extensions.
`packages/utils/observable/src/react/useObservableRef.ts`	Adds explicit relative extensions.
`packages/utils/observable/src/react/useObservableInputState.ts`	Adds explicit hook import extensions.
`packages/utils/observable/src/react/useObservableFlow.ts`	Adds explicit type import extensions.
`packages/utils/observable/src/react/useObservableEffect.ts`	Adds explicit type import extensions.
`packages/utils/observable/src/react/useObservable.ts`	Adds explicit relative extensions.
`packages/utils/observable/src/react/useDebounce.ts`	Uses the explicit types entry point.
`packages/utils/observable/src/react/use-observable-epic.ts`	Adds an explicit hook import extension.
`packages/utils/observable/src/react/index.ts`	Adds explicit React barrel extensions.
`packages/utils/observable/src/operators/switch-map-action.ts`	Adds explicit operator import extensions.
`packages/utils/observable/src/operators/map-prop.ts`	Uses the explicit types entry point.
`packages/utils/observable/src/operators/map-action.ts`	Adds explicit operator import extensions.
`packages/utils/observable/src/operators/index.ts`	Adds explicit operator barrel extensions.
`packages/utils/observable/src/operators/filter-action.ts`	Uses the explicit types entry point.
`packages/utils/observable/src/index.ts`	Adds explicit root barrel extensions.
`packages/utils/observable/src/FlowSubject.ts`	Adds explicit internal module extensions.
`packages/utils/observable/src/create-state.ts`	Adds explicit internal module extensions.
`packages/utils/observable/src/create-reducer.ts`	Adds explicit type import extensions.
`packages/utils/observable/src/actions/utils.ts`	Adds an explicit action import extension.
`packages/utils/observable/src/actions/predicates.ts`	Adds explicit action import extensions.
`packages/utils/observable/src/actions/index.ts`	Adds explicit action barrel extensions.
`packages/utils/observable/src/actions/create-async-action.ts`	Adds explicit action import extensions.
`packages/utils/observable/src/actions/create-action.ts`	Adds explicit import and export extensions.
`packages/utils/observable/src/actions/ActionError.ts`	Adds an explicit type import extension.
`packages/utils/observable/src/actions/action-mapper.ts`	Adds an explicit type import extension.

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Relative import/export specifiers in @equinor/fusion-observable's source lacked file extensions (e.g. './operators' instead of './operators/index.js'). Under the package's inherited moduleResolution: bundler tsconfig, tsc never adds them, so the compiled ESM output only resolves for bundler-based consumers. Consumers resolving the published dist directly under strict Node.js ESM (e.g. vitest without a bundler) fail with module-not-found errors. Add explicit .js/.js/index.js extensions to every relative import/export in src, and override the package's own tsconfig to module/moduleResolution: nodenext so tsc enforces this going forward instead of silently regressing.

github-actions Bot added 🐞 bug Something isn't working 🛠️ utils packages related to utils labels Aug 16, 2026

odinr requested a balanced review from Copilot August 16, 2026 20:09

Copilot started reviewing on behalf of odinr August 16, 2026 20:10 View session

Copilot AI reviewed Aug 16, 2026

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odinr marked this pull request as ready for review August 16, 2026 20:15

odinr requested a review from a team as a code owner August 16, 2026 20:15

odinr merged commit 6639e6e into next Aug 16, 2026
9 checks passed

odinr deleted the fix/observable-esm-import-extensions branch August 16, 2026 20:15

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fix(observable): add explicit extensions to relative ESM imports - #5307

fix(observable): add explicit extensions to relative ESM imports#5307
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odinr commented Aug 16, 2026

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