Compatibility handling with other APIs

[vizagite]

@ACTCD @quoid has explained some details in #790 for GM. vs GM_ issues, the former being Promise oriented.

I am recently making an userscript where I am expecting thousands of end users for a problem it solves (not all being technical) and my script is simple enough to not bother for Promises.

for safari compatibility, I found only this and tampermonkey. I love to add compatibility to userscripts even though my default script used violentmonkey-tampermonkey three different GM_ API calls only.

As I dont have safari, i just want to cross-check if this fallbacks are decent or should I keep any other things in mind? i will be injecting all css once (i have yet to first commit the repo to show u full code) and will handle that full css styles injected once with js in script:

if (typeof GM_addStyle !== "undefined") {
  GM_addStyle(css);
} else if (typeof GM !== "undefined" && typeof GM.addStyle === "function") {
  GM.addStyle(css).catch(console.error);
}

function setValue(key, value) {
  try {
    if (typeof GM_setValue !== "undefined") {
      GM_setValue(key, value);
      return;
    }

    if (typeof GM !== "undefined" && typeof GM.setValue === "function") {
      GM.setValue(key, value).catch(err => {
        console.error("GM.setValue failed:", err);
      });
    }
  } catch (err) {
    console.error("setValue error:", err);
  }
}

function getValue(key, defaultValue, callback) {
  try {
    if (typeof GM_getValue !== "undefined") {
      const value = GM_getValue(key, defaultValue);
      callback?.(value);
      return value;
    }

    if (typeof GM !== "undefined" && typeof GM.getValue === "function") {
      GM.getValue(key, defaultValue)
        .then(value => callback?.(value))
        .catch(err => {
          console.error("GM.getValue failed:", err);
          callback?.(defaultValue);
        });
    }
  } catch (err) {
    console.error("getValue error:", err);
    callback?.(defaultValue);
  }
}

thanks.

---

Edit:

// @resource worldMap https://upload.wikimedia.org/wikipedia/commons/thumb/a/ac/World_location_map.svg/1280px-World_location_map.svg.png

const IMG_URL =
  typeof GM_getResourceURL === "function"
    ? GM_getResourceURL("worldMap")
    : "https://upload.wikimedia.org/wikipedia/commons/thumb/a/ac/World_location_map.svg/1280px-World_location_map.svg.png";

const image = document.createElement("img"); 
image.src = IMG_URL;

[ACTCD]

I think they should work. But I also think unless you need to be compatible with some very old systems/browsers (whose security has become a more major issue), just using the GM. API is enough and gets the greatest compatibility.

my script is simple enough to not bother for Promises.

To be honest, I don't think Promise adds any complexity, it's just a more modern non-blocking syntax specification, and GM4.0 directly deprecated the old GM_ API in favor of just GM..

If it were me, I'd throw away all glue code and just use the GM. API, almost all modern script managers supports them.

[ACTCD]

And for your second example:

// @resource worldMap https://upload.wikimedia.org/wikipedia/commons/thumb/a/ac/World_location_map.svg/1280px-World_location_map.svg.png

const IMG_URL =
  typeof GM_getResourceURL === "function"
    ? GM_getResourceURL("worldMap")
    : "https://upload.wikimedia.org/wikipedia/commons/thumb/a/ac/World_location_map.svg/1280px-World_location_map.svg.png";

const image = document.createElement("img"); 
image.src = IMG_URL;

I think it's better to just write, for best compatibility:

const IMG_URL = "https://upload.wikimedia.org/wikipedia/commons/thumb/a/ac/World_location_map.svg/1280px-World_location_map.svg.png";

const image = document.createElement("img"); 
image.src = IMG_URL;

[vizagite]

Thanks I will try with async/await

And for your second example:

thanks, i just read grabbing it as Resource will cache the image inside the script storage indefinitely by violentmonkey without relying on browser cache policies and re-fetches; as this is static URL with no change I thought using that ResourceURL will benefit most non userscripts users as VM and TM supports it. ( I let go of GreaseMonkey support)

[ACTCD]

Just as I added here, the browser's caching mechanism is already sufficient to handle most scenarios, rather than relying on the varying implementations of script managers.

• Implement getResourceURL, getResourceText, @resource #224 (comment)

Like onatbas mentioned here that this may not align with your expectations:

In Tampermonkey settings, under the "Externals" section, it'll let you choose the update interval for the external resources. You can set it to "Always," which means downloading a fresh copy of external resources every time, without needing any change in the key whatsoever. By default, this setting is set to "Every Day" in Tampermonkey, but I use it in "Always" mode to get a fresh copy.

That is why I always recommend using modern, more reliable native APIs whenever possible, rather than relying on the varying implementations of individual extensions.

[vizagite]

By default, this setting is set to "Every Day" in Tampermonkey,

oh I didnt know that; in VM it gets at first and keeps it as default static until user does manual refresh on script page - https://violentmonkey.github.io/api/metadata-block/#resource

browser's caching mechanism is already sufficient to handle most scenarios

not exactly in the way of @resource reasoning, I replied in that other thread u tagged.

[ACTCD]

Therefore, relying on these features across extensions is highly unreliable, which is why I recommend using the native API as much as possible and maintaining the smallest GM APIs. That been said, I remain open to the possibility that we will still consider implementing and maintaining them if there are valid use cases and irreplaceable.