Fallback to Microsoft Edge if not installed Chrome

[yhatt]

Microsoft has started rolling out new Edge browser based on Chromium. It will gradually be made available on Windows Update.

This fact is lucky for Marp CLI. PDF/PPTX conversion and preview mode has to install an extra Chrome/Chromium browser. Currently, it also works with Edge by setting CHROME_PATH environment variable.

It means the most of Windows 10 user will get the compatible browser without to do anything by user. If Marp CLI was supported fallback to Edge, installing extra browser won't be needed when converting Markdown into PDF/PPTX.

[ShGKme]

Isn't it work of chrome-launcher package?

CLI just uses path from launcher:

marp-cli/src/utils/puppeteer.ts

Line 75 in 003fb6b

;[executablePath] = Launcher.getInstallations()

[yhatt]

@ShGKme chrome-launcher is only designed for Google Chrome and Chromium, not for Chromium-flavored browsers such as Edge.

[ShGKme]

@yhatt But if CHROME_PATH is set to C:\Program Files (x86)\Microsoft\Edge\Application\msedge.exe, it works fine.

If it's not work for chrome-launcher, then maybe it's possible to add check to puppeteer.ts, that process.platform === 'win32' and msedge exists on usual paths.

I may do a PR if this solution is ok.

[yhatt]

In short term the limited fallback to Edge in Windows would be no problem. However, eventually we have to use (or create) Chromium Edge finder for Windows, macOS, and Linux as same as chrome-finder.ts in chrome-launcher.

[ShGKme]

Edge is default only on Windows.

I thought, the idea was that windows users should be able to use already installed Edge without any actions as it is. Just because it works and the browser is already installed.

If any user has a normally installed Chrome, it would be found by chrome-launcher.
If user only has something unusual (like Brave or Edge on Mac), then user must provide the path. Same if user has browser installed to non-usual place.

Right now Edge has only 1 (ok, +1 more for Beta version) place to be installed by default in Windows (%programfiles%\Microsoft\Edge\Application\msedge.exe).

Of course, another way is to use some 3rd package, which would found any chromium-based browser on any OS. And add cli arg for choose like in Cypress.

[yhatt]

Here is the one of reliable way to resolve the executable path of Edge, by Microsoft (microsoft/vscode-edge-devtools):
https://github.com/microsoft/vscode-edge-devtools/blob/5056752615b3f4332dc27242b008699075dcefce/src/utils.ts#L494-L524