Module not found: wdio-electron-service/preload

[mig8447]

Hello,

• I'm using electron with JS (Not TS)

• Specifically using require (CJS) for importing modules

• I could make the examples work by changing the extension of the test file to mjs so that it is treated as a module

• When trying to enable browser.electron I added the following line to main.js:

  if ( process.env.TEST === 'true' ) require( 'wdio-electron-service/main' );

  and I added the following to my preload.js

  if ( process.env.TEST === 'true' ) require( 'wdio-electron-service/preload' );

• The require for main works without an issue, however, the require for preload throws the following error in devtools:

  Error: module not found: wdio-electron-service/preload
      at preloadRequire (VM4 sandbox_bundle:2:85095)
      at <anonymous>:7:39
      at runPreloadScript (VM4 sandbox_bundle:2:85847)
      at VM4 sandbox_bundle:2:86106
      at VM4 sandbox_bundle:2:86261
      at ___electron_webpack_init__ (VM4 sandbox_bundle:2:86265)
      at VM4 sandbox_bundle:2:86388

• I found the following note at https://www.electronjs.org/docs/latest/tutorial/sandbox#preload-scripts

  Because the require function is a polyfill with limited functionality, you will not be able to use CommonJS modules to separate your preload script into multiple files. If you need to split your preload code, use a bundler such as webpack or Parcel.

  Which I suspect is the cause for the module not being found

Would you know how to make this work using Vanilla CJS?

---

Update:

• I added webpack and bundled the preload script without success

• I also disabled the sandbox without success.

• By now when the application is packaged/built with electron-builder, a message appears saying:

  Error: module not found: wdio-electron-service/main

I'm not sure what else to try

---

Update:

I bumped into https://github.com/goosewobbler/wdio-electron-service-example which is a perfect example of a testable CJS electron application. Hope it helps others too.

I found out that when loading a web extension into Electron, WDIO opens the context of the extension window, and if that window doesn't use the preload script then the test fails.

[mig8447]

I figured it out. I am still not sure why, I was going deeper into the matter (Dig into the chromedriver launching code) and I thought of "moving" the extension loading code to the end of the "ready" event handler and that did the trick.

So bottom line, if you're loading extensions into Electron, you should do that at the end of the "ready" event handler. Otherwise, the chromedriver will attach to the first extension's background page.

[goosewobbler]

This is useful info, I'll add it to the docs.