donmccurdy/glTF-Transform

Join throws error: Cannot read properties of null (reading 'getCount')

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#1,748 opened on Oct 31, 2025

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 (4 comments) (0 reactions) (0 assignees)TypeScript (196 forks)auto 404
buggood first issuepackage:functions

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Description

Describe the bug

Using join on a particular GLTF, after a merge, crash

To Reproduce call join on a mesh I'm wondering if does not relate to an issue weld had and was fixed about gltf with points.

Expected behavior Should not crash.

Versions:

  • Version: 4.2.1
  • Environment: CLI, Ubunutu, WSL2

Additional context I'm not sure I can provide the GLTF file as it is not public data.

Contributor guide

Research direction
Investigate the join function in the glTF Transform library. The error 'Cannot read properties of null (reading 'getCount')' indicates that some object is null when accessing its getCount method. Look for places where getCount is called on a potentially null reference, particularly in the join operation. Check if the issue is related to meshes without primitives or empty geometry. Trace the merge and join logic to find where null checks are missing.
Tech stack
typescript
Domain
computer graphics
Issue type
Bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Needs investigation
Prerequisites
TypeScriptGitNode.js
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
60