GM APIs Usage Recommendation

[Malix-Labs]

Hello!

How would you recommend using GM APIs: is it better to use GM_* or GM.*?
What are the benefit of one on the other?

Thanks!

[7nik]

When only one choice is possible:
a) you want your userscript to be compatible with Greasemonkey - it supports only GM.* (but it supports only a few of them);
b) the userscript must run at document-start, read settings or some other data and do something synchronously - GM_*.

The only difference for the rest cases is that for GM.*, you need to add await and often declare functions as async. Note, now the top-level await is supported.

Technically, GM.* may have an implementation with less impact on the page-loading performance. Still, on the other hand, it'd be weird to have two separate implementations of sync and async API doing the same thing. Anyway, I don't know much about this and don't want to speculate.

[7nik]

let someOption = GM_getValue("some option name"); - no await, no delay, no way for other (page's) code to be executed - there are cases when userscript must complete initialization before page scripts run.

[Malix-Labs]

I wonder, can you use close with GM_openInTab for example?
I would like to use information stored on another page to use in the main page.
the ideal would be that the opened tab get run in the background, without focus

[7nik]

If you want to scrape some info from a page, using GM_XHR to get the HTML and extract the info is better. If the info is loaded dynamically, use GM_XHR to access the info's endpoint.

[Malix-Labs]

If you want to scrape some info from a page, using GM_XHR to get the HTML and extract the info is better. If the info is loaded dynamically, use GM_XHR to access the info's endpoint.

Thanks for that suggestion!

---

Still, do you know how to do

use close with GM_openInTab for example

[7nik]

According to the docs, it should be like this:

const tab = GM_openInTab("https://www.example.com/");

// latter
tab.close();

// somewhere else
if (tab.closed) {
  // tab is closed
  // maybe you want to re-open in
  // or complain to the user about the closed tab
} else {
  doSomeAction();
}

// and this can be done too
tab.addEventListener("close", (event) => {
  //I dunno if `event` will contain something useful. You can log it to check out
  doSomeActionOnClose(); - // there various popups that get self-closed
});