fix(form-core): handle string array indices in prefixSchemaToErrors #1689

jiji-hoon96 · 2025-08-12T04:15:30Z

Description

This PR fixes a bug in the prefixSchemaToErrors function within standardSchemaValidator.ts where array indices passed as strings (like '0', '1') were not being properly converted to bracket notation, causing validation errors for array fields to be incorrectly formatted.

Problem

Standard Schema validation libraries handle array indices differently:
- Zod: passes numeric indices (0, 1, 2)
- Yup: passes string indices ('0', '1', '2')
The existing code only checked for typeof normalizedSegment === 'number', missing string-based indices
This caused paths like people.0.name instead of the correct people[0].name

Solution

Enhanced the array index detection logic to handle both numeric and string indices
Added regex pattern /^\d+$/ to identify string representations of numbers
Maintained backward compatibility with existing numeric index handling
Ensured TypeScript type safety throughout the changes

Related Issue

Fixes #1683

Type of Change

Bug fix (non-breaking change which fixes an issue)
New feature (non-breaking change which adds functionality)
Breaking change (fix or feature that would cause existing functionality to not work as expected)
This change requires a documentation update

Testing

Added comprehensive test cases covering:
- Numeric array indices (Zod compatibility)
- String array indices (Yup compatibility)
- Nested arrays with mixed index types
- Regular object paths without arrays
All existing tests continue to pass
New tests verify the fix works correctly

Test Results

✓ standard schema validator > array path handling > should handle numeric array indices correctly
✓ standard schema validator > array path handling > should handle string array indices correctly (Yup compatibility)  
✓ standard schema validator > array path handling > should handle nested arrays with mixed numeric and string indices
✓ standard schema validator > array path handling > should handle regular object paths without array indices

Code Changes

Before

return typeof normalizedSegment === 'number'
  ? `[${normalizedSegment}]`
  : normalizedSegment

After

// Check if segment is a number or a string that represents a valid array index
const isArrayIndex = 
  typeof normalizedSegment === 'number' ||
  (typeof normalizedSegment === 'string' && /^\d+$/.test(normalizedSegment))

return isArrayIndex
  ? `[${normalizedSegment}]`
  : normalizedSegment

Impact

✅ Fixes array field validation error display issues
✅ Maintains compatibility with all existing Standard Schema implementations
✅ No breaking changes to existing functionality
✅ Improves developer experience when using array validations

Checklist

My code follows the style guidelines of this project
I have performed a self-review of my own code
I have commented my code, particularly in hard-to-understand areas
I have made corresponding changes to the documentation (if applicable)
My changes generate no new warnings
I have added tests that prove my fix is effective or that my feature works
New and existing unit tests pass locally with my changes
Any dependent changes have been merged and published in downstream modules

- Fix array path handling for Standard Schema validators - Support both numeric (Zod) and string (Yup) array indices Fixes TanStack#1683

nx-cloud · 2025-08-12T08:39:17Z

View your CI Pipeline Execution ↗ for commit 7428688

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☁️ Nx Cloud last updated this comment at 2025-08-13 09:28:35 UTC

pkg-pr-new · 2025-08-12T08:41:06Z

More templates

@tanstack/angular-form

npm i https://pkg.pr.new/@tanstack/angular-form@1689

@tanstack/form-core

npm i https://pkg.pr.new/@tanstack/form-core@1689

@tanstack/lit-form

npm i https://pkg.pr.new/@tanstack/lit-form@1689

@tanstack/react-form

npm i https://pkg.pr.new/@tanstack/react-form@1689

@tanstack/solid-form

npm i https://pkg.pr.new/@tanstack/solid-form@1689

@tanstack/svelte-form

npm i https://pkg.pr.new/@tanstack/svelte-form@1689

@tanstack/vue-form

npm i https://pkg.pr.new/@tanstack/vue-form@1689

commit: 7428688

codecov · 2025-08-12T08:42:10Z

Codecov Report

❌ Patch coverage is 90.00000% with 2 lines in your changes missing coverage. Please review.
⚠️ Please upload report for BASE (main@9e092e2). Learn more about missing BASE report.
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
packages/form-core/src/standardSchemaValidator.ts	90.00%	2 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1689   +/-   ##
=======================================
  Coverage        ?   90.51%           
=======================================
  Files           ?       37           
  Lines           ?     1698           
  Branches        ?      424           
=======================================
  Hits            ?     1537           
  Misses          ?      144           
  Partials        ?       17

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LeCarbonator

Looks promising! Thanks for tackling the issue. Let me know if you need more info or help with the PR.

packages/form-core/src/standardSchemaValidator.ts

packages/form-core/tests/standardSchemaValidator.spec.ts

…validator by inspecting form values

…/form into feat/standard-schema

… error handling

jiji-hoon96 · 2025-08-12T16:28:15Z

Thank you for the excellent feedback! Your suggestions were spot-on and made the implementation much more robust.

I really appreciate you pointing out the numeric object property issue and providing the better approach using actual form values as reference. The Array.isArray(currentFormValue) solution is much more reliable than my initial regex approach.

I've committed all the changes incorporating your feedback

✅ Form value reference instead of regex detection
✅ Updated test descriptions and replaced mocks with Zod's superRefine
✅ Added the numeric property test case
✅ All tests passing

Please review when you have a chance. Thanks for the great mentorship!

dlindahl · 2025-08-12T21:04:35Z

Appreciate the work here, but something made me wonder... in the interest of openness, has this PR been created by AI by any chance?

jiji-hoon96 · 2025-08-13T03:34:22Z

I wrote the bug fix logic myself. However, I did refer to some reference materials while searching for an efficient way to implement the code. Could this be a problem?

dlindahl · 2025-08-13T16:52:02Z

@jiji-hoon96 I am not making any claims on the work itself. I was asking just out of curiosity based on the PR itself. No worries! ✌️

LeCarbonator

LGTM! Let's see what the users from the issue have to say about it.

fix(form-core): handle string array indices in prefixSchemaToErrors

e885078

- Fix array path handling for Standard Schema validators - Support both numeric (Zod) and string (Yup) array indices Fixes TanStack#1683

ci: apply automated fixes and generate docs

b3f6cd1

LeCarbonator requested changes Aug 12, 2025

View reviewed changes

jiji-hoon96 added 3 commits August 13, 2025 01:21

fix(form-core): improve array index path handling in standard schema …

86ff708

…validator by inspecting form values

Merge branch 'feat/standard-schema' of https://github.com/jiji-hoon96…

a4f7dba

…/form into feat/standard-schema

refactor(react-core): simplify path construction in schema validation…

0eee89a

… error handling

jiji-hoon96 requested a review from LeCarbonator August 12, 2025 16:27

ci: apply automated fixes and generate docs

7428688

LeCarbonator approved these changes Aug 13, 2025

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fix(form-core): handle string array indices in prefixSchemaToErrors #1689

fix(form-core): handle string array indices in prefixSchemaToErrors #1689

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jiji-hoon96 commented Aug 12, 2025

Description

Problem

Solution

Related Issue

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Testing

Test Results

Code Changes

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Impact

Checklist

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