Hello, i just started a new project and wanted to use the latest TypeScript 5.0 version. Sadly it does not work with BabylonJS 5.53.0 because of errors like this:
node_modules/@babylonjs/core/Engines/engine.d.ts:3312:14 - error TS2717: Subsequent property declarations must have the same type. Property 'FRAMEBUFFER_ATTACHMENT_TEXTURE_NUM_VIEWS_OVR' must be of type '38448', but here has type 'number'.
3312 readonly FRAMEBUFFER_ATTACHMENT_TEXTURE_NUM_VIEWS_OVR: number;
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
node_modules/typescript/lib/lib.dom.d.ts:10509:14
10509 readonly FRAMEBUFFER_ATTACHMENT_TEXTURE_NUM_VIEWS_OVR: 0x9630;
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
'FRAMEBUFFER_ATTACHMENT_TEXTURE_NUM_VIEWS_OVR' was also declared here.
I know that there are workarounds but it would be nice if it would work out of the box. Are there any plans to support TypeScript 5.0 directly?
Hi, I have the same error but with Typescript 4.9.5 and BabylonJS 6.0. I checked the installed packages.
BabylonJS 5.57.1 works fine for me, but as soon as I try 6.0.0 I get the same problem as @Kesshi .
Maybe it is also a question of tsconfig?
"compileOnSave": false,
"compilerOptions": {
"allowJs": true,
"baseUrl": "./",
"outDir": "./dist/out-tsc",
"forceConsistentCasingInFileNames": true,
"strict": true,
"noImplicitOverride": true,
"noPropertyAccessFromIndexSignature": true,
"noImplicitReturns": true,
"noFallthroughCasesInSwitch": true,
"sourceMap": true,
"declaration": false,
"downlevelIteration": true,
"experimentalDecorators": true,
"moduleResolution": "node",
"importHelpers": true,
"target": "ES2022",
"module": "es2020",
"lib": [
"es2020",
"dom"
"useDefineForClassFields": false
"angularCompilerOptions": {
"enableI18nLegacyMessageIdFormat": false,
"strictInjectionParameters": true,
"strictInputAccessModifiers": true,
"strictTemplates": true
I can only assume you have the exact opposite error?
This was fixed for 6.0.0, as the newest lib.dom.d.ts has the definitions of those variables.
Can you share your project so I can find a solution that will work with all versions?
With Babylonjs 6.0.0 and Typescript 4.9.5 I’ve got the following errors:
ERROR(TypeScript) Subsequent property declarations must have the same type. Property 'FRAMEBUFFER_ATTACHMENT_TEXTURE_NUM_VIEWS_OVR' must be of type 'number', but here has type '38448'.
FILE node_modules/@babylonjs/core/Engines/engine.d.ts:3371:14
3369 | interface OVR_multiview2 {
3370 | framebufferTextureMultiviewOVR(target: GLenum, attachment: GLenum, texture: WebGLTexture | null, level: GLint, baseViewIndex: GLint, numViews: GLsizei): void;
> 3371 | readonly FRAMEBUFFER_ATTACHMENT_TEXTURE_NUM_VIEWS_OVR: 0x9630;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
3372 | readonly FRAMEBUFFER_ATTACHMENT_TEXTURE_BASE_VIEW_INDEX_OVR: 0x9632;
3373 | readonly MAX_VIEWS_OVR: 0x9631;
3374 | readonly FRAMEBUFFER_INCOMPLETE_VIEW_TARGETS_OVR: 0x9633;
ERROR(TypeScript) Subsequent property declarations must have the same type. Property 'FRAMEBUFFER_ATTACHMENT_TEXTURE_BASE_VIEW_INDEX_OVR' must be of type 'number', but here has type '38450'.
FILE node_modules/@babylonjs/core/Engines/engine.d.ts:3372:14
3370 | framebufferTextureMultiviewOVR(target: GLenum, attachment: GLenum, texture: WebGLTexture | null, level: GLint, baseViewIndex: GLint, numViews: GLsizei): void;
3371 | readonly FRAMEBUFFER_ATTACHMENT_TEXTURE_NUM_VIEWS_OVR: 0x9630;
> 3372 | readonly FRAMEBUFFER_ATTACHMENT_TEXTURE_BASE_VIEW_INDEX_OVR: 0x9632;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
3373 | readonly MAX_VIEWS_OVR: 0x9631;
3374 | readonly FRAMEBUFFER_INCOMPLETE_VIEW_TARGETS_OVR: 0x9633;
3375 | }
ERROR(TypeScript) Subsequent property declarations must have the same type. Property 'MAX_VIEWS_OVR' must be of type 'number', but here has type '38449'.
FILE node_modules/@babylonjs/core/Engines/engine.d.ts:3373:14
3371 | readonly FRAMEBUFFER_ATTACHMENT_TEXTURE_NUM_VIEWS_OVR: 0x9630;
3372 | readonly FRAMEBUFFER_ATTACHMENT_TEXTURE_BASE_VIEW_INDEX_OVR: 0x9632;
> 3373 | readonly MAX_VIEWS_OVR: 0x9631;
| ^^^^^^^^^^^^^
3374 | readonly FRAMEBUFFER_INCOMPLETE_VIEW_TARGETS_OVR: 0x9633;
3375 | }
3376 |
ERROR(TypeScript) Subsequent property declarations must have the same type. Property 'FRAMEBUFFER_INCOMPLETE_VIEW_TARGETS_OVR' must be of type 'number', but here has type '38451'.
FILE node_modules/@babylonjs/core/Engines/engine.d.ts:3374:14
3372 | readonly FRAMEBUFFER_ATTACHMENT_TEXTURE_BASE_VIEW_INDEX_OVR: 0x9632;
3373 | readonly MAX_VIEWS_OVR: 0x9631;
> 3374 | readonly FRAMEBUFFER_INCOMPLETE_VIEW_TARGETS_OVR: 0x9633;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
3375 | }
3376 |
3377 | abstract class OVR_multiview2 implements OVR_multiview2 {}
Typescript also supports to specify which version of the lib.dom should be used. See: https://www.typescriptlang.org/docs/handbook/release-notes/typescript-4-5.html#supporting-lib-from-node_modules
In my case (TS 5.0 with BabylonJS 5.53.0) i added this line in the dependecies to solve the problem: "@typescript/lib-dom": "npm:@types/[email protected]":
Here is also an (outdated) list of versions: GitHub - microsoft/TypeScript-DOM-lib-generator: Tool for generating dom related TypeScript and JavaScript library files
So in your case this could work (without skipLibCheck: true): "@typescript/lib-dom": "npm:@types/[email protected]"
I just tried Version 6 with TS 5 but it still does not work. I get this error:
node_modules/typescript/lib/lib.dom.d.ts:14990:11 - error TS2430: Interface 'WebGL2RenderingContext' incorrectly extends interface 'WebGL2RenderingContextBase'.
Types of property 'MIN' are incompatible.
Type 'number' is not assignable to type '32775'.
14990 interface WebGL2RenderingContext extends WebGL2RenderingContextBase, WebGL2RenderingContextOverloads, WebGLRenderingContextBase {
~~~~~~~~~~~~~~~~~~~~~~
The problem is here i think: Babylon.js/webgl2.d.ts at master · BabylonJS/Babylon.js · GitHub
MIN is defined as number but in the lib-dom its defined as 0x8007.
That’s right. But still - people are expecting that to work out of the box, and I can understand them.
To be honest, I think the best solution would be to remove those duplicated declaration, as typescript now supports them.
I will suggest a draft PR with a fix that will work for both typescript versions (hopefully 
).
Thanks again for following up on this.
