Albert Martinez

@albertdbio

Chrome Extension Debugging

Using chrome.runtime.lastError to debug Plasmo asset paths

Sometimes debugging feels more like detective work than coding. I recently ran into a case where Chrome notifications weren’t showing up in my Plasmo-based extension. I suspected a permissions problem, but everything checked out.

After a few hours of debugging I came across chrome.runtime.lastError which you can use a such:

chrome.notifications.create({
  type: 'basic',
  iconUrl: 'icon.png',
  title: 'Notifications',
  message: 'Notifications are now enabled.'
}, () => {
  const lastError = chrome.runtime.lastError
  if (lastError) {
    console.error('Last error:', lastError)
  }
})

Sure enough, lastError reported that my icon path was invalid. The fix was to import the icon properly:

import myIcon from "url:/assets/icon.png"

chrome.notifications.create({
  type: 'basic',
  iconUrl: myIcon,
  title: 'Notifications',
  message: 'Notifications are now enabled.'
}, () => {
  const lastError = chrome.runtime.lastError
  if (lastError) {
    console.error('Last error:', lastError)
  }
})

And that was that—problem solved. The lesson? Whenever something silently fails in a Chrome extension, chrome.runtime.lastError can pinpoint the exact cause. Debugging is all about noticing the subtle details that trip up our assumptions.