Function alloc

host/dom/src/main/state.js:16–24

(n)

    const files = [];

    const alloc = (n) => {
        if (n === null || n === undefined) return HANDLE_NONE;
        nodes.push(n);
        const h = nodes.length - 1;
        let set = handleByEl.get(n);
        if (!set) { set = new Set(); handleByEl.set(n, set); }
        set.add(h);
        return h;
    };

    const node = (h) => {
        if (h < 0 || h >= nodes.length || nodes[h] === null) {