flatten arrays

flatten.js

/**
 * Normalizes recursive VNode lists by flattening all nodes, filtering out `null` children and converting strings to
 * text nodes.
 */
export function normalizeVNodes(nodes: VNodeRecursiveList): VNode<any>[] {
    for (let i = 0; i < nodes.length; i++) {
        const n = nodes[i];

        if (n === null || Array.isArray(n)) {
            let copy = nodes.slice(i);
            const flatten = nodes.slice(i) as VNode<any>[];

            while (copy.length > 0) {
                const item = copy.shift();
                if (item !== null) {
                    if (Array.isArray(item)) {
                        copy = (item as any).concat(copy);
                    } else {
                        flatten.push(typeof item === "string" ? $t(item) : item as VNode<any>);
                    }
                }
            }

            return flatten;
        } else if (typeof n === "string") {
            nodes[i] = $t(n);
        }
    }

    return nodes as VNode<any>[];
}