Skip to content

Instantly share code, notes, and snippets.

What would you like to do?
Preload feature detection
var DOMTokenListSupports = function(tokenList, token) {
if (!tokenList || !tokenList.supports) {
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");
if (!linkSupportsPreload) {
// Dynamically load the things that relied on preload.

This comment has been minimized.

Copy link

triblondon commented Jun 30, 2016

If you wanted to reduce the code bloat for production, would this do?

var supportsPreload = (function() { try { document.createElement("link").relList.supports('preload'); return 1 } catch(e) { return 0; }}());

This comment has been minimized.

Copy link

lsuchanek commented Mar 7, 2018

@triblondon I think, better solution is: var supportsPreload = (function() { try { return document.createElement("link").relList.supports('preload'); } catch(e) { return false; }}());

Your code return false positive for FF 58.

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
You can’t perform that action at this time.