yoavweiss · January 10, 2020 17:36 · superpoincare · Aug 9, 2016
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");
    }
  }
 };

 var linkSupportsPreload = DOMTokenListSupports(document.createElement("link").relList, "preload"); // true
 var classListSupportsFoobar = DOMTokenListSupports(document.createElement("div").classList, "foobar"); // undefined + console.log
 var linkSupportsFoobar = DOMTokenListSupports(document.createElement("link").relList, "foobar"); // false
	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");
	}
	}
	};

	var linkSupportsPreload = DOMTokenListSupports(document.createElement("link").relList, "preload"); // true
	var classListSupportsFoobar = DOMTokenListSupports(document.createElement("div").classList, "foobar"); // undefined + console.log
	var linkSupportsFoobar = DOMTokenListSupports(document.createElement("link").relList, "foobar"); // false