// getChildren(win) - returns array of windows that are child to `win`
// isTrue(win) - just a random callback

function recurseDFS(win) {
    // depth first
    let coll = [];
    coll.push(isTrue(win));
    let children = getChildren(win);
    for (let child of children) {
        coll.push(...recurseDFS(child));
    }
    return coll;
}

function recurseBFS(win) {
    // breadth first
    let coll = [];
    let todo = [win];

    while (todo.length) {
        let cur = todo.shift();
        coll.push(isTrue(cur));
        todo.push(...getChildren(cur));
    }

    return coll;
}