Recursive iteration over dynamically nested object array

Question

I am using angular JS and one of their examples:http://jsfiddle.net/furf/EJGHX/

I need to take the data when the update function occurs and add some values to it bef

Answer 1

If I'm understanding you correctly, you want each 'child' to have a parentID (defined by its parent; 0 otherwise) and an index (based on its position within it sibling set).

function normalize(parent) {
    if (parent && parent.children) {
        for (var i = 0, l = parent.children.length; i < l; ++i) {
            var child = parent.children[i];
            child.index = i;
            if (!child.parentId) child.parentId = parent.id || '0';
            normalize(child);
        }
    }
}

normalize(data);

Answer 2

Recursion is calling function inside the same function. Your sample is not a recursion at all;

function runRecursive(input) {
    for (var i = 0, l = input.length; i < l; i++) {
        var current = input[i];

        parentid = current.id == null ? '0' : current.id;
        current.index = i;
        if (current.children && current.children.length > 0) {
            runRecursive(current.children);
        };
    };
};

runRecursive(data.children);

Also you should define i and l with var keyword, otherwise it will be located in window context and recursion logic will broken. Though I don't get what is parentid variable for and why it defined outside visible code.