Develop Reference

When parsing XML with recursive function, how do I return a string or array from that function?

I've got a working recursive function which goes through an XML doc looking for a matching node name, and then logging matching values...I'm trying to modify it to return a string or an array, and can't figure it out.
This is in Google Apps script. I've tried passing in a blank string into the function, and then returning it at the end, but it doesn't work. Here is the working Logger function:
function logChildren(elements, dataRequired){
for (var i = 0; i < elements.length; i++) {
if (elements[i].getName() == dataRequired){
Logger.log(elements[i].getText());
}
if(elements[i].getContentSize() > 1){
var children = elements[i].getChildren();
logChildren(children, dataRequired);
}
}
};
I tried passing in an empty string, and then returning it like this but it doesn't work:
function logChildren(elements, dataRequired, str){
for (var i = 0; i < elements.length; i++) {
if (elements[i].getName() == dataRequired){
str = str + ", " + elements[i].getText();
}
if(elements[i].getContentSize() > 1){
var children = elements[i].getChildren();
logChildren(children, dataRequired, str);
}
}
return str
};
How do I get a string or array OUT of this function, rather than just console logging it?

Instead of returning str try without it, because str will have all the values. If you return str it might collapse the current iteration. Please let us know whether this worked

Providing your elements is already parsed and valid, this should work.
function logChildren(elements, dataRequired){
values = [];
req = elements.getElementsByTagName(dataRequired);
for (var i = 0; i < req.length; i++) {
values.push(req[i].childNodes[0].nodeValue);
}
return values
};
elements = "<house>" +
"<name>hello</name>" +
"<town>world</town>" +
"<name>cat</name>" +
"<folder>" +
"<name>kitty</name>" +
"</folder>" +
"</house>";
p = new DOMParser();
elements = p.parseFromString(elements, "text/xml");
newValues = logChildren(elements, "name")
console.log(newValues);
I've included my own little xml just to test, and it returns an array.
As you can see, getElementsByTagName even returns values in sub folders.

You should use a global variable or another function, so that the output variable str is outside the scope of the recursed function.
var str = "";//holds all data of recursion
function logChildren(elements, dataRequired){
..
str += ", " + elements[i].getText();
..
}

indexOf in an array not behaving correctly

I'm attempting to use JS to check a string for the most amount of the letters and append that result to a div. It looks so far like this:
var string = "AABBCCDDEEEEEEEEEE";
var stringInput = document.getElementById("string");
function showMostChar() {
var newInput = string.split("");
var inputAsArray = Array.of(newInput);
for (i = 0; i > inputAsArray; i++) {
if ((inputAsArray.indexOf("E")) > 9 ) {
stringInput.innerHTML = "E";
}
}
}
window.onload = showMostChar;
<div id="string"></div>
In plain english, I'm looking to split a string by character, which I then use to create an array. I loop through the array and if E has more than 9 (an arbitrary value) put E into the div. before I was using array() but I remembered thats not a valid function, so I did research and found Array.of() but I'm not seeing anything appended to string div.
is Array.of() not the right way to create an array in this context? If not why?
The ideal scenario is to log the total amount of characters that appear the most, so in this instance EEEEEEEEEE. I need to somehow get the value of each character and compare it to each other, somehow...something like:
for (i = 0; i > inputAsArray; i++) {
// somehow compare values to each other? e being each instance
// so, would that be a loop within a loop?
if ((i.value()) > e ) {
stringInput.innerHTML = i;
}
}

There are few things that needs to be fixed in your code:
First of all .split() will return an array so newInput is
already an array, you don't need any transform it.
In the other hand the right method to create a new array is
Array.from(), because Array.of() takes a Number as
argument.
Second thing you don't need any loop to check for the .indexOf(), you can directly call it upon newInput array.
And it wasn't entering the if block because .indexOf() will return
the first index of E in the array, which is lower than 9, I
used 5 for testing purpose here.
This is how should be your code:
function showMostChar() {
var newInput = string.split("");
if ((newInput.indexOf("E")) > 5 ) {
stringInput.innerHTML = "E";
}
}
Demo:
var string = "AABBCCDDEEEEEEEEEE";
var stringInput = document.getElementById("string");
function showMostChar() {
var newInput = string.split("");
console.log(newInput);
if ((newInput.indexOf("E")) > 5) {
stringInput.innerHTML = "E";
}
}
window.onload = showMostChar;
<div id="string"></div>
Edit:
To get the number of occurrences of E in the array, you can use Array.filter() like this:
function getNumberOfOccurences(char) {
var newInput = string.split("");
return newInput.filter(function(c){
return c === char;
}).length;
}
console.log(getNumberOfOccurences("E"));
Demo:
var string = "AABBCCDDEEEEEEEEEE";
var stringInput = document.getElementById("string");
function getNumberOfOccurences(char) {
var newInput = string.split("");
return newInput.filter(function(c){
return c === char;
}).length;
}
console.log(getNumberOfOccurences("E"));

Access object property name with for loop

I'm working on Emoji system based on JavaScript & Github Emoji icons , I use a function to trigger typing event, that's my code
function myFunction() {
var y = document.getElementById("myInput").value;
var x = y.replace(/plus/g,'<img width="25" src="https://assets-cdn.github.com/images/icons/emoji/unicode/1f44d.png?v7" />');
document.getElementById("demo").innerHTML = "You wrote: " + x;
}
it's working well , but it's not smart .
I tried using an Array with for loop to handle the Github Emoji API
var data = {
star: "https://assets-cdn.github.com/images/icons/emoji/unicode/2b50.png?v7"
};
for (var i in data) {
console.log(data[i]);
}
the for loop access the object property but not display it's name , I need the property name for replacement , the final code I expect is :
for (vari in data) {
var x = string.replace(/${property_name}/g, data[i]);
}

Try this:
for (var key in data) {
if (data.hasOwnProperty(key)) {
var x = string.replace(new RegExp(key, "g"), data[key]);
}
}
When you use a for(var i in data) loop i is the object property not data[i]
Also, if you want to construct a regex pattern from a string you'll have to create a RegExp object.

For completeness, a better way might be to avoid the loop and make use of .replaces ability to take a callback function:
var data = {
star: "https://assets-cdn.github.com/images/icons/emoji/unicode/2b50.png?v7"
};
var pattern = new RegExp(Object.keys(data).join('|'), 'g');
var x = string.replace(pattern, function(match) { return data[match]; });

Implementing wildcard at end of a string

I looked through a number of posts (and other websites) and I seem to have a hit a roadblock. I have the following array:
var data_dictionary = ["youtube.com", "facebook.com", "youtube.com/feed/subscriptions", "twitter.com"]
I'm trying to return data for everything that has youtube.com*. Below is the relevant snippet of my function:
var result = []
for (var i=0; i<data_dictionary.length; i++) {
if (data_dictionary[i].page == /^youtube.com/) {
result.push (data_dictionary[i].page,data_dictionary[i].share)
}
}
break;
}
return result
The problematic area is in the if clause (/^youtube.com/). How can I receive the following return:
["youtube.com" , "youtube.com/feed/subscriptions"]

You can use Array.prototype.filter() method to filter array and RegExp.prototype.test() to check for match.
var data_dictionary = ["youtube.com", "facebook.com", "youtube.com/feed/subscriptions", "twitter.com"];
function check(data_dictionary) {
return data_dictionary.filter(function(v) {
return /^youtube\.com/.test(v);
// using indexOf
// v.indexOf('youtube.com') == 0;
});
}
console.log(check(data_dictionary));
FYI: Your if condition will be only true if the string is '/^youtube.com/'. ie, ('/^youtube.com/' == /^youtube.com/) === true. Your code will work if you changed the if condition to /^youtube.com/.test(data_dictionary[i]). Also in the provided data page and share properties are undefined only plain strings are the element.

Using the same approach that you had before. However using ".filter" won't be a bad idea, but I will suggest you compare their benchmark
var data_dictionary = ["youtube.com", "facebook.com", "youtube.com/feed/subscriptions", "twitter.com"];
var pattern = /^youtube.com/;
var result = [];
var i = 0;
function loop (args) {
for (i; i < args.length; i++) {
if (pattern.test(args[i])) {
result.push(args[i]);
}
}
return result;
}
console.log(loop(data_dictionary)) // ["youtube.com" , "youtube.com/feed/subscriptions"]
Comparing the speed below I would suggest you use the approach above

No need for regex here you can do like this;
var data_dictionary = ["youtube.com", "facebook.com", "youtube.com/feed/subscriptions", "twitter.com"],
filtered = data_dictionary.filter(e => !!~e.indexOf("youtube.com") && e);
document.write("<pre>" + JSON.stringify(filtered) + "</pre>");
Or if you want a faster solution still with Array methods then
var data_dictionary = ["youtube.com", "facebook.com", "youtube.com/feed/subscriptions", "twitter.com"],
filtered = data_dictionary.reduce((p,c) => !!~c.indexOf("youtube.com") ? p.concat(c):p,[]);
document.write("<pre>" + JSON.stringify(filtered) + "</pre>");

Javascript Eval to work for both function and plain string

I want to display a list of items, now sometimes these items' title will just be a plain string, and sometimes it might be a value returned by a function.
How can I make both events work using eval() ?
Here is an example code:
var a1 = "formatDate('" + startTime + "') + ' - ' + formatDate('" + endTime + "')"
var a2 = "#america"
var result1 = eval(a1) // works well!
var result2 = eval(a2) // doesn't work, need to use eval('a2') but then first one doesn't work
Only thing I can think of is when creating the string for example "#america" have it saved like "'#america'" instead, but I would rather avoid it
[edit]
Eventually I will have something like this:
arr.push("formatDate('" + startTime + "') + ' - ' + formatDate('" + endTime + "')");
arr.push("#america");
for(var i = 0; i < arr.length; i++) {
var ev = eval(arr[i]);
console.log(ev);
}

What I would suggest is wrapping the eval in a try catch block, if the eval succeeds then return the value otherwise return the value originally passed to function. There are many cases where eval can fail as it is simply trying to parse the string as valid JavaScript so any invalid JS not just a simple string can cause it to fail so its better to be safe and catch any error that comes out of it.
var evaluate = function(value) {
try {
return eval(value);
}
catch(err)
{
return value;
}
}

var ev = eval(a2) would be equivalent to var ev = eval('#america') which doesn't make any real sense.
When you say eval('a2') works, I assume that ev = '#america' is the desired outcome. The 'a2' expression is evaluated as simply accessing the value of the variable of that name.
You're basically just having a series of strings that may be valid javascript code, or may not, and there's no way to tell which is which. In that case, the best you can do is something like
try {
ev = eval(arr[i]);
} catch(ex) {
ev = arr[i];
}
... which obviously looks terrible. Can you control the content of the entries in arr?
arr.push(function() {
return formatDate(startTime) - formatDate(endTime);
});
arr.push("#america");
In that case, you could check for the type of each entry, and act on it accordingly:
for(var i = 0; i < arr.length; i++) {
var ev = typeof arr[i] == 'function' ? arr[i]() : arr[i];
console.log(ev);
}

this is that i should do:
var a1 = function(){
return formatDate(startTime) + formatDate(endTime)
}
var a2 = "#america"
var result1 = a1();
var result2 = a2;
Yo can check with typeof(a1) if the var is a function or an object or anyting else.
if(typeof(a1)=='function'){
result = a1();
}else{
result=a1;
}