fix(form-core): fix deleteField method #1809

kusiewicz · 2025-10-14T18:14:45Z

🎯 Changes

If this idea make sense, I will add tests

After calling form.deleteField('fieldName'), the field is removed from form.state.values, but after a moment it returns with defaultValue and appears at the end of the values object.

The problem occurred due to React lifecycle and the logic in FieldApi.mount()

Sequence of events:

User clicks delete -> form.deleteField('field') executes -> value is remo ved from form.state.values -> field metadata is removed - cool, but
React detects state change -> component re-renders
During re-render the field is still in the DOM (not unmounted)
React calls FieldApi.update() or lifecycle hooks -> this calls setFieldValue
In FieldApi.mount() there was logic:

   if ((this.options.defaultValue as unknown) !== undefined) {
     this.form.setFieldValue(this.name, this.options.defaultValue as never, {
       dontUpdateMeta: true,
     })
   }

I think this uncoditionally restored defaultValue on every mount.update

PS: Even if we add a check in mount() - setFieldValue can be called from other places (e.g., from FieldApi.update() during React lifecycle).

I added a mechanism for tracking intentionally deleted fields to prevent their their accidental restoration.

Added _deletedFields: Set<string> in FormApi - it stores names of fields that were intentionally deleted by the user
deleteField() adds the field to _deletedFields
setFieldValue() blocks operations on deleted fields

✅ Checklist

I have followed the steps in the Contributing guide.
I have tested this code locally with pnpm test:pr.

🚀 Release Impact

This change affects published code, and I have generated a changeset.
This change is docs/CI/dev-only (no release).

changeset-bot · 2025-10-14T18:14:49Z

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nx-cloud · 2025-10-14T18:15:20Z

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☁️ Nx Cloud last updated this comment at 2025-12-15 11:31:57 UTC

pkg-pr-new · 2025-10-14T18:16:07Z

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commit: 3b5d966

LeCarbonator · 2025-10-15T06:23:51Z

Blocked by #1729 . This seems critical to test with the linked PR.

crutchcorn · 2025-12-01T19:39:32Z

@kusiewicz can you fix merge conflicts and then @LeCarbonator if you could, re review for @kusiewicz since the blocker is merged?

Thanks!

kusiewicz · 2025-12-02T08:16:58Z

@kusiewicz can you fix merge conflicts and then @LeCarbonator if you could, re review for @kusiewicz since the blocker is merged?

Thanks!

Will do today!

codecov · 2025-12-15T11:32:16Z

Codecov Report

❌ Patch coverage is 93.33333% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 89.74%. Comparing base (6892ed0) to head (3b5d966).
⚠️ Report is 104 commits behind head on main.

Files with missing lines	Patch %	Lines
packages/form-core/src/FormApi.ts	90.90%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1809      +/-   ##
==========================================
- Coverage   90.35%   89.74%   -0.62%     
==========================================
  Files          38       48      +10     
  Lines        1752     1940     +188     
  Branches      444      483      +39     
==========================================
+ Hits         1583     1741     +158     
- Misses        149      178      +29     
- Partials       20       21       +1

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LeCarbonator

Sort of looks promising, but looking at the cause of the initial problem, it was because of the way defaultValues were handled in fieldApi.update. They have been changed in the recent updates due to arrays being stale.

I can't reproduce the linked issue on the latest TSF version. Can you confirm?

If the issue still exists, then I think this implementation would make sense. Adding tests to avoid regression would be needed before a merge, but let's confirm that it's still a needed fix first.

LeCarbonator · 2025-12-19T08:10:46Z

packages/form-core/src/FormApi.ts

+    if (this._deletedFields.has(field as string)) {
+      return
+    }
+
+    if (!opts?.dontUpdateMeta) {
+      this._deletedFields.delete(field as string)
+    }


This feels like a no-op.

If the field is in the set, you return early.

If the field is not in the set, delete it from the set.

LeCarbonator · 2025-12-19T08:11:31Z

packages/form-core/src/FormApi.ts

    const dontRunListeners = opts?.dontRunListeners ?? false
    const dontValidate = opts?.dontValidate ?? false

+    if (this._deletedFields.has(field as string)) {


Use your newly added isFieldDeleted instead.

kusiewicz · 2025-12-20T15:12:07Z

Sort of looks promising, but looking at the cause of the initial problem, it was because of the way defaultValues were handled in fieldApi.update. They have been changed in the recent updates due to arrays being stale.

I can't reproduce the linked issue on the latest TSF version. Can you confirm?

If the issue still exists, then I think this implementation would make sense. Adding tests to avoid regression would be needed before a merge, but let's confirm that it's still a needed fix first.

Guys, problem does not exist in the newest main version - I think it can be closed.

@LeCarbonator @crutchcorn

LeCarbonator · 2025-12-20T17:39:36Z

Well, glad to hear! Closing the PR, then.

kusiewicz mentioned this pull request Oct 23, 2025

removeFieldValue keeps data from subfields when used with form.AppField - unable to delete last row in AgGrid #1820

Open

fix(form-core): fix deleteField method

28cd997

kusiewicz force-pushed the fix-delete branch from d0d2271 to 28cd997 Compare December 15, 2025 11:28

ci: apply automated fixes and generate docs

3b5d966

LeCarbonator requested changes Dec 19, 2025

View reviewed changes

LeCarbonator closed this Dec 20, 2025

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fix(form-core): fix deleteField method #1809

fix(form-core): fix deleteField method #1809

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