Structured cloning of WebAssembly.Memory is not defined

At least Gecko and WebKit support serializing & deserializing WebAssembly.Memory objects. Yet https://webassembly.github.io/spec/web-api/#serialization only covers WebAssembly.Module.

I also couldn't find test coverage for this on WPT.

Just to clarify, this is only serializing/deserializing shared WebAssembly.Memory right? I don't think Gecko supports doing that for unshared memories. You could make a copy of the underlying ArrayBuffer if you want, but it's not transferable.

Technically the threads proposal hasn't merged yet, and so shared memory isn't defined here yet. I looked upstream though and it is missing a definition for this in the specification there.

I created some tentative tests here to clarify what I mean and what I think the specification needs to require: web-platform-tests/wpt#59748.

Serialization & deserialization of WebAssembly.Memory

Bug 2038126 [wpt PR 59748] - Serialization & deserialization of WebAs…

Serialization & deserialization of WebAssembly.Memory

Bug 2038126 [wpt PR 59748] - Serialization & deserialization of WebAs…

Navigation Menu

Repository navigation

Structured cloning of WebAssembly.Memory is not defined #2155

Metadata

Assignees

Labels

Type

Projects

Milestone

Relationships

Development

Structured cloning of WebAssembly.Memory is not defined #2155

Description

Activity

eqrion commented on May 7, 2026

annevk commented on May 8, 2026

Metadata

Metadata

Assignees

Labels

Type

Projects

Milestone

Relationships

Development

Issue actions