set_icons.js

// Readable
fetch("https://raw.githubusercontent.com/DDoS/sprite-icons/master/output/icons.json")
.then(res => res.json())
.then((icons) => {
    for (key in icons) {
        localStorage[key.replace("id", "icon")] = icons[key].url;
    }
});

// Compressed
fetch("https://raw.githubusercontent.com/DDoS/sprite-icons/master/output/icons.json").then(r=>r.json()).then((i)=>{for(k in i){localStorage[k.replace("id","icon")]=i[k].url;}});