misc/wasm: add support for loading wasm files inside WebWorker #26192
Description
What version of Go are you using (go version)?
go1.11beta1 windows/amd64
Does this issue reproduce with the latest release?
yes
What operating system and processor architecture are you using (go env)?
set GOARCH=wasm
set GOBIN=
set GOCACHE=C:\Users\leidegre\AppData\Local\go-build
set GOEXE=
set GOHOSTARCH=amd64
set GOHOSTOS=windows
set GOOS=js
set GOPATH=C:\Users\leidegre\go
set GOPROXY=
set GORACE=
set GOROOT=C:\Users\leidegre\sdk\go1.11beta1
set GOTMPDIR=
set GOTOOLDIR=C:\Users\leidegre\sdk\go1.11beta1\pkg\tool\windows_amd64
set GCCGO=gccgo
set CC=gcc
set CXX=g++
set CGO_ENABLED=0
set CGO_CFLAGS=-g -O2
set CGO_CPPFLAGS=
set CGO_CXXFLAGS=-g -O2
set CGO_FFLAGS=-g -O2
set CGO_LDFLAGS=-g -O2
set PKG_CONFIG=pkg-config
set GOGCCFLAGS=-fPIC -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fdebug-prefix-map=C:\Users\leidegre\AppData\Local\Temp\go-build848467850=/tmp/go-build -gno-record-gcc-switches
set VGOMODROOT=What did you do?
I tried to run the compiled code in a WebWorker process. It did not work at first but through a series of changes I got it to work, the issue was primarily with the bootstrapping process. Tested in Firefox, Chrome and Edge.
What did you expect to see?
It would be nice if the bootstrapping code from misc/wasm worked out of the box for WebWorker processes.
What did you see instead?
Errors that globals, like window did not exist.
Suggested change
The offending line https://github.com/golang/go/blob/master/misc/wasm/wasm_exec.js#L30 can be changed to something like this to work around the issue.
if (typeof window !== "undefined") {
window.global = window;
} else if (typeof self !== "undefined") {
self.global = self;
} else {
throw new Error("cannot export Go")
}self is the equivalent of window when running within a WebWorker process.