Document speedscope global installation

[jean-francois-labbe]

Speedscope must be installed globally for the graph to be displayed.

[technicalpickles]

Did you get an error without this? We use npx to run it:

If any requested packages are not present in the local project dependencies, then they are installed to a folder in the npm cache, which is added to the PATH environment variable in the executed process. A prompt is printed (which can be suppressed by providing either --yes or --no).

Maybe the prompt is causing a problem 🤔

[jean-francois-labbe]

Absolutely. The error is not visible in the terminal.

This command
❯ open /var/folders/6v/dj23h5vd0ynd697fvtksqglw0000gn/T/speedscope-1679663586339-61260.html
Opens the browser but the page is blank.

cat the file the browser opens

❯ cat  /var/folders/6v/dj23h5vd0ynd697fvtksqglw0000gn/T/speedscope-1679663586339-61260.html
<script>window.location="file:///Users/jeff/.npm/_npx/61260/lib/node_modules/speedscope/dist/release/index.html#localProfilePath=/var/folders/6v/dj23h5vd0ynd697fvtksqglw0000gn/T/speedscope-1679663586339-61260.js"</script>

The generated html file is referring to speedscope index.html the file here

❯ ls /Users/jeff/.npm/_npx/61260/lib/node_modules/speedscope/dist/release/index.html
ls: /Users/jeff/.npm/_npx/61260/lib/node_modules/speedscope/dist/release/index.html: No such file or directory (os error 2).

But it doesn't exist on my computer.

So I looked at speedscope documentation and found the npm install -g speedscope command. I ran it. Now it works.

[technicalpickles]

Thanks, that's useful context. Mostly asking so I can make sure to solve this correctly and completely.

Before singed, I was using a command snippet that included npx, so if it did need to be installed, it was an interactive prompt so I could accept it. I adapted that snippet for this library, and seems I never didn't have speedscope installed 😮‍💨

At the very least, I think it's reasonable to check speedscope is available before calling, and don't try to open it in that case. We could call alternatively/additionally callnpx --yes speedscope to handle installing it, but that kinda seems rude 🤔

[technicalpickles]

I think we can get better error checking that this is available, but this is an improvement over not having any docs.