Develop Reference

Stuck between JSON nested object & Callback in Nodejs

My application calls the module to parse nested JSON object, to read values of 2 keys.
parseData(str, function (error, str) {
if (err) {
console.log("Error - parseData : ", err);
} else {
console.log(str);
}
And the parseData module is as follows
function parseData(str, callback) {
function recursiveFunction(obj) {
var keysArray = Object.keys(obj);
for (var i = 0; i < keysArray.length; i++) {
var key = keysArray[i];
var value = obj[key];
if (value === Object(value)) {
parseData(value);
} else {
if (key == 'title') {
title = value;
}
if (key == 'extract') {
var extract = value.replace(/(\r\n|\n|\r)/gm," ");
callback(null, JSON.stringify('{"title":'+ title + ', "text":' + extract));
}
}
}
}
recursiveFunction(str);
}
But it shows following error
/modules/parseData.js:22
callback(null, JSON.stringify('{"title":'+ title + ', "text":' + extract));
^
TypeError: callback is not a function
Why is callback failing ? How to return back JSON object ?
EDIT
There were some errors in the code and now corrected.
function parseData(str, callback) {
function recursiveFunction(obj) {
var keysArray = Object.keys(obj);
for (var i = 0; i < keysArray.length; i++) {
var key = keysArray[i];
var value = obj[key];
if (value === Object(value)) {
recursiveFunction(value);
} else {
if (key == 'title') {
title = value;
}
if (key == 'extract') {
var extract = value.replace(/(\r\n|\n|\r)/gm," ");
callback(null, JSON.stringify('{"title":'+ title + ', "text":' + extract));
}
}
}
}
recursiveFunction(str);
};

You're calling parseData(value); and not passing a callback; pass callback if you want that original callback to be used.

Javascript Callback in for Loop

My problem is that I'm having a Function A which calls at one point another function, let's call it Function B (getChildContent) and needs the return value of Function B in order to proceed. I know that it's because of Javascripts Asynchronous Nature, and i tried to solve it with a callback. But i can't get it work properly.
FunctionA(){
//some Code.....
else {
for(i in clustertitles) {
if(S(text).contains(clustertitles[i])) {
var parent = {};
parent.ClusterName = clustertitles[i];
parent.Functions = [];
var str = '== ' + clustertitles[i] + ' ==\n* ';
str = S(text).between(str,'.').s;
var caps = parseFunctions(str);
for(y in caps) {
//var content = getChildContent(caps[y]);
getChildContent(caps[y], function(content) { //Function call
var child = {};
child.FunctionName = caps[y];
child.Content = [];
child.Content.push(content);
parent.Functions.push(child);
console.log(content);
});
}}}
}
function getChildContent (capname, callback) {
t = capname.replace(' ', '_');
bot.page(t).complete(function (title, text, date) {
var str = S(text).between('== Kurzbeschreibung ==\n* ', '.').s;
if(str === undefined || str === null || str === '') {
throw new Error('Undefined, Null or Empty!');
}
else {
var content = {};
str = parseTitles(str);
content.Owner = str[0];
content.Aim = str[1];
content.What = str[2];
content.Who = str[3];
content.Steps = str[4];
content.Page = 'some URL';
callback(content);
}
});
}
So in Function A I'm trying to call getChildContent from a for-Loop and pass the current string from caps-array. For each String in caps-array getChildContent() makes a http request over a node.js module and retrieves a string. With this string i'm building an object (content) which is needed in Function A to continue. However the 'console.log(content)' in Function A just prints out the object which is created with the last string in caps-array, but for many times. E.G. if caps-array has 5 entries, i get 5 times the object which is created with the last entry of caps-array.
How can i manage the loop/callback to get every time the right object on my console?

Your loop should call another function that preserves the value of y, something like this:
FunctionA(){
//some Code.....
else {
for(i in clustertitles) {
if(S(text).contains(clustertitles[i])) {
var parent = {};
parent.ClusterName = clustertitles[i];
parent.Functions = [];
var str = '== ' + clustertitles[i] + ' ==\n* ';
str = S(text).between(str,'.').s;
var caps = parseFunctions(str);
for(y in caps) {
yourNewFunction (y, caps, parent);
}}}
}
function yourNewFunction (y, caps, parent) {
getChildContent(caps[y], function(content) { //Function call
var child = {};
child.FunctionName = caps[y];
child.Content = [];
child.Content.push(content);
parent.Functions.push(child);
console.log(content);
});
}
function getChildContent (capname, callback) {
t = capname.replace(' ', '_');
bot.page(t).complete(function (title, text, date) {
var str = S(text).between('== Kurzbeschreibung ==\n* ', '.').s;
if(str === undefined || str === null || str === '') {
throw new Error('Undefined, Null or Empty!');
}
else {
var content = {};
str = parseTitles(str);
content.Owner = str[0];
content.Aim = str[1];
content.What = str[2];
content.Who = str[3];
content.Steps = str[4];
content.Page = 'some URL';
callback(content);
}
});
}

There are 2 ways to do so.
Put the loop inside a function, execute your callback after the loop is done. (Problematic if you are doing async call inside the loop.
function doLoopdiloopStuff() {
for() {
}
callback();
}
The other way, the way i prefer looks like this:
for(var i = 0; i < stuff || function(){ /* here's the callback */ }(), false; i++) {
/* do your loop-di-loop */
}
In another example:
for (var index = 0; index < caps.length || function(){ callbackFunction(); /* This is the callback you are calling */ return false;}(); index++) {
var element = caps[index];
// here comes the code of what you want to do with a single element
}

overwriting a property in a string

Is there someone out there who can help me with this function. What it suppose to do is set a property in a string and this string is split firstly by a colon (:) for each control and the it checks if there is an id matching and if there is it then checks if there is a property matching if there is a property overwrite the value but my function doesn't seem to overwrite the property it just returns the original string. can someone help
var cookieValue = 'id=1&state=normal&theme=purple:id=2&state=maximized&theme=pink:id=3&state=maximized&theme=black';
var setProperties = function (cookie, id, prop, prop_value) {
var windows = cookie.split(':');
var result = $.each(windows, function(index, value) {
var temp1 = [];
if(value.indexOf(id) > -1) {
var temp2 = [];
var properties = value.split('&');
var result2 = $.each(properties, function(index, value) {
if(value.indexOf(prop) > -1) {
temp3 = [];
temp3 = value.split('=');
temp3[1] = prop_value;
temp2.push(temp3.join('='));
}else {
temp2.push(value);
}
return temp2.join('&')
});
temp1.push(result2.join('&'));
return temp1
}
else{
temp1.push(value);
}
return temp1;
})
return alert(result.join(':'));
}
setProperties(cookieValue, '2', 'theme', 'black');

Try:
function setProperties(cookie, id , name, value) {
var sections = $.map(cookie.split(":"), function (section) {
var pairs, found = false;
if (section.indexOf("id=" + id) === 0) {
pairs = $.map(section.split("&"), function (pair) {
if (pair.indexOf(name + "=") === 0) {
found = true;
return name + "=" + value;
} else {
return pair;
}
});
if (!found) {
pairs.push(name + "=" + value);
}
return pairs.join("&");
} else {
return section;
}
});
return sections.join(":");
}

Each doesn't return a value. You had some semicolons missing I edited the code a little.
It's not production worthy but at least it returns the (partially) correct value.
You will have to figure out how to replace that value in the cookie. I think regex is the best approach or of course you can pass temp1 array between the function but you will have to re-factor your code quite a lot.
var cookieValue = 'id=1&state=normal&theme=purple:id=2&state=maximized&theme=pink:id=3&state=maximized&theme=black';
var setProperties = function (cookie, id, prop, prop_value) {
var windows = cookie.split(':');
var result = $.each(windows, function(index, value) {
var temp1 = [];
console.log('value' + value);
console.log('windows' + windows);
console.log(cookieValue);
if(value.indexOf(id) > -1) {
var temp2 = [];
var properties = value.split('&');
var windows = $.each(properties, function(index, value) {
if(value.indexOf(prop) > -1) {
temp3 = [];
temp3 = value.split('=');
temp3[1] = prop_value;
temp2.push(temp3.join('='));
}else {
temp2.push(value);
}
cookieValue = temp2.join('&');
});
temp1.push(temp2.join('&'));
cookieValue = temp1;
}
else{
temp1.push(value);
}
cookeValue = temp1;
})
console.log("new cookie" + cookieValue); // PRINTS new cookieid=2&state=maximized&theme=black
}
setProperties(cookieValue, '2', 'theme', 'black');

Dynamically building array, appending values

i have a bunch of options in this select, each with values like:
context|cow
context|test
thing|1
thing|5
thing|27
context|beans
while looping through the options, I want to build an array that checks to see if keys exist, and if they don't they make the key then append the value. then the next loop through, if the key exists, add the next value, comma separated.
the ideal output would be:
arr['context'] = 'cow,test,beans';
arr['thing'] = '1,5,27';
here's what i have so far, but this isn't a good strategy to build the values..
function sift(select) {
vals = [];
$.each(select.options, function() {
var valArr = this.value.split('|');
var key = valArr[0];
var val = valArr[1];
if (typeof vals[key] === 'undefined') {
vals[key] = [];
}
vals[key].push(val);
});
console.log(vals);
}

Existing code works by changing
vals=[];
To
vals={};
http://jsfiddle.net/BrxuM/

function sift(select) {
var vals = {};//notice I made an object, not an array, this is to create an associative array
$.each(select.options, function() {
var valArr = this.value.split('|');
if (typeof vals[valArr[0]] === 'undefined') {
vals[valArr[0]] = '';
} else {
vals[valArr[0]] += ',';
}
vals[valArr[0]] += valArr[1];
});
}
Here is a demo: http://jsfiddle.net/jasper/xtfm2/1/

How about an extensible, reusable, encapsulated solution:
function MyOptions()
{
var _optionNames = [];
var _optionValues = [];
function _add(name, value)
{
var nameIndex = _optionNames.indexOf(name);
if (nameIndex < 0)
{
_optionNames.push(name);
var newValues = [];
newValues.push(value);
_optionValues.push(newValues);
}
else
{
var values = _optionValues[nameIndex];
values.push(value);
_optionValues[nameIndex] = values;
}
};
function _values(name)
{
var nameIndex = _optionNames.indexOf(name);
if (nameIndex < 0)
{
return [];
}
else
{
return _optionValues[nameIndex];
}
};
var public =
{
add: _add,
values: _values
};
return public;
}
usage:
var myOptions = MyOptions();
myOptions.add("context", "cow");
myOptions.add("context","test");
myOptions.add("thing","1");
myOptions.add("thing","5");
myOptions.add("thing","27");
myOptions.add("context","beans");
console.log(myOptions.values("context").join(","));
console.log(myOptions.values("thing").join(","));
working example: http://jsfiddle.net/Zjamy/

I guess this works, but if someone could optimize it, I'd love to see.
function updateSiftUrl(select) { var
vals = {};
$.each(select.options, function() {
var valArr = this.value.split('|');
var key = valArr[0];
var val = valArr[1];
if (typeof vals[key] === 'undefined') {
vals[key] = val;
return;
}
vals[key] = vals[key] +','+ val;
});
console.log(vals);
}

Would something like this work for you?
$("select#yourselect").change(function(){
var optionArray =
$(":selected", $(this)).map(function(){
return $(this).val();
}).get().join(", ");
});
If you've selected 3 options, optionArray should contain something like option1, option2, option3.

Well, you don't want vals[key] to be an array - you want it to be a string. so try doing
if (typeof vals[key] === 'undefined') {
vals[key] = ';
}
vals[key] = vals[key] + ',' + val;

Calling Method represented by string

I am being passed a string similar to below.
"Users_Controller.login"
"Users_Controller" represents the object below.
And "login" a method within it.
var Users_Controller = ( function () {
return{
login : function(vo, callback)
{......}
}
})();
Given only the string as a pointer,is it possible call the method?

You can use this function:
function getPropertyFromString(str, start) {
str = str.split(".");
var prop = start || window;
for (var i = 0; i < str.length; i++) {
if(prop == undefined)
return prop;
else
prop = prop[str[i]];
}
return prop;
}
getPropertyFromString("Users_Controller.login");
However, this does not allow bracket syntax.

Something like this?
var Users_Controller = (function () {
return {
login: function (name) {
alert("hello " + name);
},
logout: function (name) { alert("goodbye "+name); }
}
})();
var methods = {};
for (method in Users_Controller) {
methods["Users_Controller." + method] = Users_Controller[method];
}
methods["Users_Controller.login"]('john');
methods["Users_Controller.logout"]('john');