Release build crash caused by runtimeType.toString() type checks (minification issue)

[seceba]

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Title

Release build crash caused by runtimeType.toString() type checks (minification issue)

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Body

### Description

In release builds, Dart minifies class names (for example `Vector3` becomes something like `aU`).  
The package currently checks types using `runtimeType.toString()`, which breaks in release mode and causes runtime crashes.

Example problematic code in `property_binding.dart`:

```dart
if (["Color", "Vector3", "Quaternion"]
    .contains(nodeProperty.runtimeType.toString()))

This works in debug/profile builds, but in release builds class names are minified, so the check fails.
As a result, Vector3 / Quaternion objects can be written directly into numeric buffers.
Later _lerp() tries to treat them as num, causing errors like:

Vector3 is not a subtype of num
PropertyMixer._lerp
AnimationMixer.update

This affects:

• Flutter web release builds
• Flutter web WASM builds
• dart2js optimized builds

Debug mode works fine, which makes the issue difficult to diagnose.

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Root Cause

Using runtimeType.toString() for type checking is not safe in release builds because Dart minifies class names.

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Suggested Fix

Replace string comparison with proper type checks using is:

if (nodeProperty is Color ||
    nodeProperty is Vector3 ||
    nodeProperty is Quaternion) {

This fix resolves the crash in release builds and works correctly across debug/profile/release.

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Environment

• Flutter: stable (3.x)
• Platform: Web (release & wasm)
• Package: three_js_animations
• Browser: Chrome, Safari

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Notes

After applying this fix locally, release builds run correctly on Chrome and Safari without crashes.

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[Knightro63]

Hi @seceba,

Thanks for letting me know I will remove all the ones I can.