Upgrade to ESLint v9 #3125

laurakwhit · 2026-01-28T22:45:24Z

Description & motivation 💭

This PR migrates from ESLint v8 legacy config to ESLint v9 with the modern flat config format and fixes various linting issues errors and warnings.

ESLint Migration

Configuration Changes:

Migrated from .eslintrc.cjs to eslint.config.js with flat config format
Upgraded typescript-eslint/eslint-plugin and typescript-eslint/parser from v6 to v8 for ESLint v9 compatibility
Replaced eslint-plugin-import with eslint-plugin-import-x (maintained fork with native flat config support)
Added proper ignores for build outputs (.vercel, .svelte-kit, etc.)

New Dependencies:

eslint/js - ESLint recommended config
typescript-eslint - Modern TypeScript ESLint package
globals - Global variable definitions
eslint-plugin-import-x - Import ordering and validation

Stylelint Configuration

Added declaration-property-value-no-unknown rule to allow Tailwind's theme() function in CSS properties

Code Quality Fixes

Portal Component Refactor:

Refactored portal.svelte to use @attach directive instead of large $effect block

Linting Error Fixes:

Fixed unused variable warnings (e.g., unused error parameters in catch blocks)
Added some missing keys to Svelte {#each} blocks
Updated Playwright tests to use modern locator API instead of deprecated waitForSelector()
Fixed various import ordering issues

Formatting:

Ran Prettier to ensure consistent code style across the codebase

Screenshots (if applicable) 📸

Design Considerations 🎨

Testing 🧪

How was this tested 👻

Manual testing
E2E tests added
Unit tests added

Steps for others to test: 🚶🏽‍♂️🚶🏽‍♀️

All linting commands should pass:

pnpm lint
pnpm eslint
pnpm stylelint

Checklists

Draft Checklist

Merge Checklist

Issue(s) closed

DT-3596

Docs

Any docs updates needed?

vercel · 2026-01-28T22:45:29Z

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Project	Deployment	Actions	Updated (UTC)
holocene	Ready	Preview, Comment	Feb 3, 2026 0:02am

temporal-cicd · 2026-01-28T22:46:27Z

src/lib/utilities/route-for.ts

-}: EventParameters): string => {
-  return `${routeForWorkflow(parameters)}/history/events/${eventId || requestId}`;
+}: EventParameters): ResolvedPathname => {
+  return resolve(`${routeForWorkflow(parameters)}/history/events/[id]`, {


⚠️ Type 'string | undefined' is not assignable to type 'string'.

temporal-cicd · 2026-01-28T22:46:30Z

	Warnings
⚠️	📊 Strict Mode: 48 errors in 8 files (17.1% of 280 total) src/lib/utilities/route-for.ts (2) L131:4: Type 'string \| undefined' is not assignable to type 'string'. L210:4: Type 'string \| undefined' is not assignable to type 'string'. src/lib/services/events-service.ts (11) L75:43: Argument of type 'EventSortOrder \| undefined' is not assignable to parameter of type 'EventSortOrder'. L78:4: Argument of type '(token: string) => Promise' is not assignable to parameter of type '(token?: NextPageToken \| undefined) => Promise'. L88:18: Property 'history' does not exist on type 'WithoutNextPageToken'. L108:20: Parameter 'full' implicitly has an 'any' type. L108:26: Parameter 'current' implicitly has an 'any' type. L114:19: Parameter 'e' implicitly has an 'any' type. L128:4: Argument of type '(token: string) => Promise' is not assignable to parameter of type '(token?: NextPageToken \| undefined) => Promise'. L142:17: Property 'history' does not exist on type 'WithoutNextPageToken'. L143:50: Property 'history' does not exist on type 'WithoutNextPageToken'. L154:28: No overload matches this call. L195:6: No overload matches this call. src/lib/utilities/is-event-type.ts (5) L214:55: Function lacks ending return statement and return type does not include 'undefined'. L241:19: Element implicitly has an 'any' type because expression of type '"userMetadata" \| "workflowExecutionStartedEventAttributes" \| "workflowExecutionCompletedEventAttributes" \| "workflowExecutionFailedEventAttributes" \| "workflowExecutionTimedOutEventAttributes" \| ... 52 more ... \| "nexusOperationCancelRequestFailedEventAttributes"' can't be used to index type 'HistoryEvent \| CommonHistoryEvent \| IterableEvent'. L460:6: 'event.markerRecordedEventAttributes' is possibly 'null' or 'undefined'. L460:6: Argument of type 'string \| null \| undefined' is not assignable to parameter of type 'string'. L494:4: 'event.workflowExecutionUpdateCompletedEventAttributes' is possibly 'null' or 'undefined'. src/lib/utilities/format-event-attributes.ts (13) L79:38: Element implicitly has an 'any' type because expression of type 'string' can't be used to index type 'CombinedAttributes'. L80:58: Element implicitly has an 'any' type because expression of type 'string' can't be used to index type 'CombinedAttributes'. L84:10: Element implicitly has an 'any' type because expression of type 'string' can't be used to index type 'CombinedAttributes'. L89:10: Element implicitly has an 'any' type because expression of type 'string' can't be used to index type 'CombinedAttributes'. L93:11: Element implicitly has an 'any' type because expression of type 'string' can't be used to index type 'CombinedAttributes'. L103:25: Element implicitly has an 'any' type because expression of type 'string' can't be used to index type 'CombinedAttributes'. L116:46: No overload matches this call. L118:25: Element implicitly has an 'any' type because expression of type 'string' can't be used to index type 'CombinedAttributes'. L124:42: Element implicitly has an 'any' type because expression of type 'string' can't be used to index type 'CombinedAttributes'. L148:23: Element implicitly has an 'any' type because expression of type 'string' can't be used to index type 'CombinedAttributes'. L207:9: Type '("userMetadata" \| "workflowExecutionStartedEventAttributes" \| "workflowExecutionCompletedEventAttributes" \| "workflowExecutionFailedEventAttributes" \| "workflowExecutionTimedOutEventAttributes" \| ... 52 more ... \| "nexusOperationCancelRequestFailedEventAttributes")[] \| undefined' must have a 'Symbol.iterator' method that returns an iterator. L230:6: Element implicitly has an 'any' type because expression of type 'string' can't be used to index type 'Partial<Record<AttributeGroup, ("userMetadata" \| "workflowExecutionStartedEventAttributes" \| "workflowExecutionCompletedEventAttributes" \| "workflowExecutionFailedEventAttributes" \| ... 53 more ... \| "nexusOperationCancelRequestFailedEventAttributes")[]>>'. L257:34: 'groupedAttributes.summary' is possibly 'undefined'. src/lib/utilities/get-single-attribute-for-event.ts (12) L126:13: 'getStackTrace' implicitly has return type 'any' because it does not have a return type annotation and is referenced directly or indirectly in one of its return expressions. L228:20: Type 'object \| null' is not assignable to type 'string \| Record<string, unknown> \| IPayloads'. L230:35: No overload matches this call. L235:20: Type 'object \| null' is not assignable to type 'string \| Record<string, unknown> \| IPayloads'. L237:53: 'value' is possibly 'null'. L237:53: Element implicitly has an 'any' type because expression of type 'string' can't be used to index type '{}'. L239:25: 'value' is possibly 'undefined'. L269:19: Function lacks ending return statement and return type does not include 'undefined'. L270:44: No overload matches this call. L308:41: Argument of type 'unknown' is not assignable to parameter of type 'Payload'. L324:46: No overload matches this call. L337:34: 'event.attempt' is possibly 'null' or 'undefined'. src/lib/holocene/menu/menu-item.svelte (2) L52:4: Type 'null' is not assignable to type 'string'. L53:4: Type 'null' is not assignable to type 'string'. src/lib/utilities/omit.ts (2) L19:6: Element implicitly has an 'any' type because expression of type 'string' can't be used to index type '{ [K in keyof Source]: Source[K]; }'. L19:20: Element implicitly has an 'any' type because expression of type 'string' can't be used to index type '{}'. src/lib/models/workflow-status.ts (1) L14:62: A type predicate's type must be assignable to its parameter's type.

Generated by 🚫 dangerJS against 997b25f

laurakwhit · 2026-01-28T22:50:14Z

eslint.config.js

+    rules: {
+      ...sharedRules,
+      'svelte/require-each-key': 'warn',
+      'svelte/no-navigation-without-resolve': 'warn',


Still getting a bunch of theses warnings despite the routing utility functions (in route-for.ts) already returning a ResolvedPathname. Seems that the ESLint rule can't detect this so either we leave as is, disable specific lines or just go ahead and disable it (e.g. add { ignoreGoto: true }).

ignoreGoto imo or just warn

I'll just leave as warn for now.

rossedfort

💯

rossedfort · 2026-02-02T19:41:07Z

src/lib/components/lines-and-dots/svg/timeline-graph-row.svelte

      <Dot
        point={[x, y]}
        classification={group.lastEvent.classification}
-        icon={'retry'}


I'm so glad eslint catches this now 🙌

rossedfort · 2026-02-02T19:41:55Z

src/lib/components/workflow/client-actions/batch-cancel-confirmation-modal.svelte

  confirmType="destructive"
  cancelText={translate('common.cancel')}
-  confirmDisabled={!jobIdValid}
+  confirmDisabled={!$jobIdValid}


Wow, this was likely causing a bug, nice!

laurakwhit added 9 commits January 28, 2026 11:11

Bump eslint and move to eslint.config file

e8ec07e

Run prettier

ac9a128

Fix stylelint error for theme()

8269960

Fix svelte/no-navigation-without-resolve

947b3dc

Fix remaining errors

2cc26e6

Fix is defined but never used warnings

3243430

Fix use of page.waitForSelector()

87881be

Fix each block should have a key

cd4428d

Refactor portal to use attach

52cf346

laurakwhit requested review from a team, Alex-Tideman and rossedfort as code owners January 28, 2026 22:45

temporal-cicd bot reviewed Jan 28, 2026

View reviewed changes

laurakwhit commented Jan 28, 2026

View reviewed changes

laurakwhit requested a review from GiantRobots January 28, 2026 22:52

vercel bot deployed to Preview February 2, 2026 19:32 View deployment

rossedfort approved these changes Feb 2, 2026

View reviewed changes

Revert each block keys

997b25f

laurakwhit force-pushed the eslint-upgrade branch from c288501 to 997b25f Compare February 3, 2026 00:01

vercel bot deployed to Preview February 3, 2026 00:02 View deployment

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Upgrade to ESLint v9 #3125

Upgrade to ESLint v9 #3125

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Description & motivation 💭

ESLint Migration

Configuration Changes:

New Dependencies:

Stylelint Configuration

Code Quality Fixes

Portal Component Refactor:

Linting Error Fixes:

Formatting:

Screenshots (if applicable) 📸

Design Considerations 🎨

Testing 🧪

How was this tested 👻

Steps for others to test: 🚶🏽‍♂️🚶🏽‍♀️

Checklists

Draft Checklist

Merge Checklist

Issue(s) closed

Docs

Any docs updates needed?

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