<script>
const graph = {
    value: 65,
    children: [{
        value: 15,
        children: [{
            value: 55,
            children: [{
                value: 85,
                children: [{
                    value: 66,
                    children: [{
                        value: 1
                    }, {
                        value: 21
                    }]
                }]
            }, {value: -30}]
        }]
    }, {
        value: -1
    }]
};

const tree = data => {
    let arr = [], cur
    while (data.children && (cur = data.children.pop())) {
        arr = arr.concat(tree(cur))
    }
    return arr.concat(data.value)
}
const arr = tree(graph)
document.write(`Min: ${Math.min(...arr)}, Max: ${Math.max(...arr)}`)

//var tree=function(a){for(var b=[],c;a.children&&(c=a.children.pop());)b=b.concat(tree(c));return b.concat(a.value)};
</script>

const average = (graph) => {
    return sum(graph) / count(graph);
};

const sum = (graph) => {
    return graph.children ? graph.children.map(sum).reduce((item1, item2) => item1 + item2, graph.value) : graph.value;
}

const count = (graph) => {
    return graph.children ? graph.children.map(count).reduce((item1, item2) => {
    return item2.value ? (item1++, item1) : item1 += item2;
    }, 1) : graph;
};

function average({ value, children = [] }, result = { sum: 0, count: 0 }) {
	result.sum += value;
	result.count++;

	for(const child of children)
		average(child, result);

	return result.sum / result.count;
}