igrigorik · June 21, 2023 16:57 · safareli · Jun 26, 2018
diff --git a/domtokenlist_feature_detection.js b/domtokenlist_feature_detection.js
 var DOMTokenListSupports = function(tokenList, token) {
  if (!tokenList || !tokenList.supports) {
    return;
  }
  try {
    return tokenList.supports(token);
  } catch (e) {
    if (e instanceof TypeError) {
      console.log("The DOMTokenList doesn't have a supported tokens list");
    } else {
      console.error("That shouldn't have happened");
    }
  }
 };

 // test if preload is supported
 var linkSupportsPreload = DOMTokenListSupports(document.createElement("link").relList, "preload"); 
 if (linkSupportsPreload) {
  // ...
 }
	var DOMTokenListSupports = function(tokenList, token) {
	if (!tokenList \|\| !tokenList.supports) {
	return;
	}
	try {
	return tokenList.supports(token);
	} catch (e) {
	if (e instanceof TypeError) {
	console.log("The DOMTokenList doesn't have a supported tokens list");
	} else {
	console.error("That shouldn't have happened");
	}
	}
	};

	// test if preload is supported
	var linkSupportsPreload = DOMTokenListSupports(document.createElement("link").relList, "preload");
	if (linkSupportsPreload) {
	// ...
	}