Develop Reference

Javascript .indexof 'typeError' error despite forcing string conversion

JS drives me insane with issues like this. I have the following code which creates a string (composed of session data and date information) to be written to an array, as such:
var _writes = String(req.session.subscriber + ":" + req.session.postal + "[" + req.session.id + "]=" + _onYear + "-" + _onMonth + "-" + _onDay + "-" + _onHour + "-" + _onMinute);
_users.push(_writes);
Later, I wish to perform an 'indexof' command on the string of the array, as such:
for (_cycle = 0; _cycle < _users.length; ++_cycle) {
_seeks = String(_users[_cycle]);
_score = _seeks.indexof("="); //ERROR THROWN HERE
//do other stuff here...
} //for loop
My error is "TypeError: _seeks.indexof is not a function"...? I thought by converting everything to a string I should be able to perform the 'indexof' command. Can somebody please advise what the issue is here? I thank you in advance.

Probably not a js issue. You are using "indexof" instead of "indexOf" (Uppercase O). Check https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/indexOf
It should be:
_seeks.indexOf("=");
Don't give up, it will make sense soon :)

parsing JSON data with java script

I use Google plus API and get this data from it and get an error while parsing this JSON data
and here is the code I use to parse this data and get error as data object is tested and work fine and hold data as it appear in past 2 images
var allIems = data.items;
for (var element in allIems) {
document.getElementById('datafromapi').innerHTML +=
(" , published time :" + element.published +
" , last updated time :" + element.updated +
", complete url : " + element.url
);
var obj = element.object.attachments;
document.getElementById('datafromapi').innerHTML +=
(+"\nattachments of post :\n" +
" type : " +
obj[0].objectType +
" ,displayName of content : " +
obj[0].displayName +
" ,content URL : " +
obj[0].url +
" ,content data :" +
obj[0].image.url +
" ,content type : " +
obj[0].image.type +
" ,content height : " +
obj[0].image.height +
" ,content width : " +
obj[0].image.width +
"\n\n\n");
}
});
i got that error appear
Uncaught TypeError: Cannot read property 'attachments' of undefined

element values in
for (var element in allIems) {
are keys of allItems, which in this case are array indices. You have to address the actual array items like this:
var obj = allItems[element].object.attachments;
Your code element.object.attachments; tries to access property object of a number, which does not exist.
Since we know that allItems is an array, you could have written:
for (var i = 0; i < allIems.length; i++) {
var obj = allItems[i].object.attachments;

Javascript has a built in JSON parser you can use that takes in a string of the data and returns an object.
let jsonDataAsString = "{\"a\":1,\"b\":2}";
let jsonDataAsObject = JSON.parse(jsonDataAsString);
Then you can traverse through the data as an object, referencing properties using dot-notation
console.log(jsonDataAsObject.a); // 1
To be safe, you should be comparing properties to null before trying to use then
if(jsonDataAsObject.somePropery != null) {
// the property exists so you can access it here
}

Returning a concatenated string from a functions' properties in javascript

I'm a total JS beginner. Here is the JsBin link formLetter test should be passing.
TL;DR
This:
var formLetter = function(recipient, msg, sender) {
return "Hello " + recipient + ",\n" + "\n" + msg + "\n" + "\nSincerely," + "\n" + sender
};
console.log(formLetter("Hermione", "Luna","How are you?"));
Should return:
"Hello Hermione,
How are you?
Sincerely,
Luna"
But instead I get this:
"Hello [object Object],
undefined
Sincerely,
undefined"
Edit
Sorry for the confusion. I'm working on different problems inside one JsBin. This is the correct JsBin with the isolated code.

This is because you are only getting one object passed into the function call. This object contains the information you need in lieu of the named arugments you have provided.
The first argument, recipient being [object Object] tells you that it's an object. undefined means that nothing was passed in their place. This signifies the common pattern of a config or param object being passed to the function call. Because of this, what you have as named arguments should really be property look ups on the object provided as the first argument.
Your function definition should look more like:
var formLetter = function (letter) {
// do something with letter
};
Inside of that function call, you may then hit the properties of the letter object to see if they contain what you need, Doing console.log debugging in dev tools will help track it down.

The line:
var formLetter = function(recipient, msg, sender) {
return "Hello " + recipient + ",\n" + "\n" + msg + "\n" + "\nSincerely," + "\n" + sender
};
in your example needs one semicolon after "sender", like:
var formLetter = function(recipient, msg, sender) {
return "Hello " + recipient + ",\n" + "\n" + msg + "\n" + "\nSincerely," + "\n" + sender;
};
Your undefined is related to the use of anidated console.log.
You do:
console.log(longMessage.formLetter("Hermione", "Luna","How are you?"));
and (in the JsBin) you have also:
var longMessage = {
formLetter: function(recipient, sender, msg) {
console.log("Hello " + recipient + ",\n" + "\n" + msg + "\n" + "\nSincerely," + "\n" + sender);
}
};
In the example of your question you have them corrected.
Double check the code you post, please.

After looking at your test in jsbin, I noticed that in your assert.deepEqual() method you run formLetter(letter) and compares it to the concatenated string you created.
The problem is that formLetter() expects three string values and you send it an object (letter). That's why you get [Object object] in the first location and undefined in the others.
You should run formLetter(letter.recipient, letter.msg, letter.sender) in your assert and it should work properly.

pass toString(number) in innerHTML

This is my first post, I am "new" to javascript but experienced in actionscript. I'm having an issue that should not be one, can't get my head around it.
In the code below all I want to do is pass a integer variable (stackID) as an img id attribute inside innerHTML. It must be some detail I just don't know but I have searched for hours on google to no avail. Help would be greatly aprreciated. Whatever I do, it seems I can only pass <img id="string">, which of course is not what I want. Can't pass <img id=numVariable>, or <img id=String(numVariable)>, there must surely be a way to do this ?
Thanks folks !
Here is the line of code :
div.innerHTML='<img src="img/xbut.png" id=String(stackID) onclick="close(this.id)">';

You're trying to pass it in the string.
What you want to do is:
div.innerHTML='<img src="img/xbut.png" id="' + String(stackID) + '" onclick="close(' + this.id + ')">';
Oh and since you're already making a string, you don't need the String() convert, you can just id="' + stackID + '"

Javascript is loosely typed and will automatically convert (to the best of its abilities) anything you want to interpolate in a string:
var num = 1;
"sup" + num; // => "sup1"
It's cool, but be careful though, it can lead to some weird surprises:
var obj = {};
"sup" + obj.missingKey; // => "supundefined"
In that case, obj.missingKey === undefined, and String(undefined) === "undefined", so "sup" + obj.missingKey becomes in fact "sup" + "undefined"

javascript has not string interpolation. Concatenate stackId like:
div.innerHTML='<img src="img/xbut.png" id="' + stackID + '" onclick="close(this.id)">';

Use '+' to join chunks like this:
div.innerHTML='<img src="img/xbut.png" id="' + String(stackID) + '" onclick="close(' + this.id + ')">';

Try this, you make the variable is dynamic:
var x = 0;
x = x +1;
div.innerHTML='<img src="img/xbut.png" id="name_' + x + '" onclick="close(this.id)">';

Getting NaN Error and undefined Error

I have a Problem with my push function in JavaScript.
<script type="text/javascript">
var myArr = []
var len = myArr.length
$.getJSON('daten.json', function(data) {
$.each(data,function(key,value) {
for(var i = 0; i <= len; i++){
myArr.push("<p>" + value.Name+i ," ", value.Nachname+i + "</p>")
}
})
$('.content').html(myArr.join(''))
})
</script>
I need to convert value.Name+i like this = value.Name0, value.Name1 and so on. I got a JSON File and the Keys are Dynamic, so the first entry got Name0 the second Name1 and so on. Now I must print the JSON file on my html page, but how I can write this line:
myArr.push("<p>" + value.Name+i ," ", value.Nachname+i + "</p>")
with my var i which increment in the loop, to call the Keys in my JSON file?
Like value.Name0. Doing value.Name+i and value.Name.i does not work.

It seems to me what you're looking for is something like this:
myArr.push("<p>" + value['Name'+i] ," ", value['Nachname'+i] + "</p>")
This portion of javascript is covered pretty nicely here: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Working_with_Objects

Take the object property in a variable, use condition to check if it has value or not then concat it
var nameval = value.name;
then use in your javascript variable
nameval+i

You need to convert your i (integer value) to string prior to adding it.
use:
value.Name + i.toString()
here's the jfiddle link: http://jsfiddle.net/kpqmp49o/