Generate html file with Bazel Emscripten toolchain

[Nerdyvedi]

Hi,
I want to generate html file in addition to wasm and javascript "glue code". I am using bazel emscripten toolchain.

I want to do something like the following
emcc hello.c -s WASM=1 -o hello.html
But not able to understand what changes I need to make in the Bazel build file to get the html file as well.

I added linkopts = [ "-o hello.html"], to the BUILD file.
But getting the following error
emcc.py did not appear to output any known files!

I tried with --oformat html
Getting this error
Customizing EXPORT_NAME is not currently possible with HTML output (see https://github.com/emscripten-core/emscripten/issues/10086)'

Then, I changed EXPORT_NAME=Module,
I get the following
Due to collision in variable name "Module", the shell file "/root/.cache/bazel/_bazel_root/7c8212d09d20008d9ab2f5e31ef362d8/external/emscripten/emscripten/src/shell.html" is not compatible with build options "-s MODULARIZE=1 -s EXPORT_NAME=Module". Either provide your own shell file, change the name of the export to something else to avoid the name collision. (see https://github.com/emscripten-core/emscripten/issues/7950 for details)

[walkingeyerobot]

Ok, this is now mostly done.

Right now the HTML minifier doesn't appear to work. While the npm package html-minifier-terser is correctly downloaded and installed, it runs it via external/emscripten/emscripten/node_modules/.bin/html-minifier-terser, which is a symlink to node_modules/html-minifier-terser/cli.js. This is correct, except cli.js has a bunch of relative paths, so running it via the symlink doesn't work. I don't yet know if this is an emscripten bug or a bazel specific bug. I think the latter is more likely, but it's also possible not a ton of people are using the html minifier and this has just gone unreported.

For now, just pass linkopts = ["--oformat=html", "-s MINIFY_HTML=0"],. I'll keep this bug open to track using the html minifier with the bazel toolchain.