json_safe.js

var util = require('util');

function json_stringify_safe(node, parents){
    parents = parents || [];

    console.log("Looking at: ", node);
    if(!node || typeof node != "object" || util.isDate(node) || util.isError(node) || util.isRegExp(node)){
        return JSON.stringify(node);
    }

    console.log("Type: ", typeof node);

    if (util.isArray(node)) {
        parents.push(node);
        var str = '[';
        for (var i=0; i < node.length; i++) {
            var value = node[i];
            if (value && typeof value == "object" && parents.indexOf(value) >= 0) {
                // circularity detected!
                str += '"[Circular]"';
            }
            else {
                str += json_stringify_safe(value, parents);
            }
            if (i != (node.length - 1)) {
                str += ',';
            }
        }
        parents.pop();
        return str + ']';
    }

    var keys = Object.keys(node);

    parents.push(node); // add self to current path      
    var str = '{';
    for (var i = 0; i < keys.length; i++) {
        str += JSON.stringify(keys[i]) + ':';
        var value = node[keys[i]];
        if (value && typeof value == "object" && parents.indexOf(value) >= 0) {
            // circularity detected!
            str += '"[Circular]"';
        }
        else {
            str += json_stringify_safe(value, parents);
        }
        if (i != (keys.length - 1)) {
            str += ',';
        }
    }
    parents.pop();
    return str + '}';
}

var list = ["a", "b", "c"]; var obj = {list: list, foo: {bar: list}};
list.push(obj);

console.log(json_stringify_safe(obj));