Develop Reference

Alternate cases in textbox Javascript

I want to make a piece of code that alternates the case of text that the user inputs. Currently, my code looks like this:
var num;
function toTitleCase(str) {
return str.replace(/\w\S*/g, function (txt) { return txt.charAt(0).toUpperCase() + txt.substr(1).toLowerCase(); });
}
$('input, textarea').onkeyup(function () {
prev = true;
for (num = 0; num < this.length; num += 2)
{
this.substr(num).val(toTitleCase(this.substr(num)));
}
});
The problem is that it doesn't work (as in nothing changes). I tried making it a Chrome extension but it doesn't change the case. Is it my way of testing the code that's weird or does the code have a bug?

Try this. Simple code. Codepen Link
$('input, textarea').keyup(function () {
var value = $(this).val();
var altText = '';
for (num = 0; num < value.length; num ++)
{
if(num%2==0)
altText += value[num].toUpperCase();
else
altText += value[num].toLowerCase();
}
$(this).val(altText);
});

Below code should work
var num;
function toTitleCase(str) {
return str.replace(/\w\S*/g, function (txt) { return txt.charAt(0).toUpperCase() + txt.substr(1).toLowerCase(); });
}
$('input, textarea').keyup(function () {
var value = $(this).val();
var char = value.slice(-1);
if(value.length%2){
var str2 = value.slice(0, -1) + toTitleCase(char);
$(this).val(str2);
}
});

Replace last letters in array of strings Javascript

I need to do as follows:
I've got an array of strings containing last names. Some of them ends with letter 'i'.
manLastNames = ["testowski","bucz","idzikowski","gosz"];
I need to make a function which will iterate over this array of strings and if there is an element ending with 'i', I need to replace this 'i' for 'a', otherwise just leave string as it is.
At the end I want to have another array where all last 'i's are replaced with 'a's.
womanLastNames = ["testowska","bucz","idzikowska","gosz"];
This is what I have now, but Im pretty sure that it start being crap at some point
var rep = function() {
var manLastNames = ["testowski","bucz","idzkowski","gosz"];
var womanLastNames = new Array(4);
for (var i=0; i<manLastNames.length; i++) {
var lastName = manLastNames[i];
if (lastName.substr(lastName.length - 1, 1) == 'i') {
lastName = lastName.substr(0, lastName.length - 1) + 'a';
}
}
for (var i=0; i<womanLastNames.length; i++) {
womanLastNames[i] = lastName[i];
}
console.log(womanLastNames);
}
rep();

Try the code:
var manNames = ["testowski","bucz","idzkowski","gosz"];
var womanNames = manNames.map(function(name) {
return name.endsWith("i") ? name.slice(0, -1) + "a" : name;
});
console.log(womanNames)
If your interpreter supports ES6, the following is equivalent:
names.map((name)=>name.endsWith("i") ? name.slice(0, -1) + "a" : name)

Here is solution
var rep = function() {
var manLastNames = ["testowski","bucz","idzkowski","gosz"];
var womanLastNames =[];
for (var i=0; i<manLastNames.length; i++) {
var lastName = manLastNames[i];
if (lastName.charAt(lastName.length - 1) == 'i') {
lastName = lastName.substr(0, lastName.length - 1) + 'a';
}
womanLastNames.push(lastName);
}
console.log(womanLastNames);
}
rep();
Another solution is to use .map method like this, using a callback function:
var manLastNames = ["testowski","bucz","idzikowski","gosz"];
function mapNames(item){
return item[item.length-1]=='i' ? item.substr(0, item.length-1) + "a" : item;
}
console.log(manLastNames.map(mapNames));

Depending on how efficient you need to be, you can use regular expressions to do both tasks:
var new_name = name.replace(/i$/, 'a');
will replace the last "i" in a string with "a" if it exists
var new_name = name.replace(/i/g, 'a');
will replace all "i"s in a string with "a".
var names = ["testowski", "bucz", "idzkowski", "gosz"];
console.log("original", names);
var last_i_replaced = names.map(function(name) {
return name.replace(/i$/, 'a');
});
console.log("last 'i' replaced", last_i_replaced);
var all_i_replaced = names.map(function(name) {
return name.replace(/i/g, 'a');
});
console.log("all 'i's replaced", all_i_replaced);

This should work:
var rep = function() {
var manLastNames = ["testowski","bucz","idzkowski","gosz"];
var womanLastNames = manLastNames;
for(var i=0; i<manLastNames.length;i++){
if(manLastNames[i].charAt(manLastNames[i].length-1)=='i'){
womanLastNames[i]=manLastNames[i].substr(0,womanLastNames[i].length-1)+'a';
}
}
console.log(womanLastNames);
}
rep();

Here is another solution
var manLastNames = ["testowski","bucz","idzkowski","gosz"];
var womanLastNames = []
manLastNames.forEach(x => {
if (x.charAt(x.length-1) === "i") womanLastNames.push(x.slice(0,-1).concat("a"));
else womanLastNames.push(x);
});
console.log(womanLastNames);

Split array by tag and delete all similar element

I have some html page with text and need to output all inner HTML from tag b by alphabetical order in lower case. I'm just a begginer, so don't be strict.
My code is here (text is just for example): http://jsfiddle.net/pamjaranka/ebeptLzj/1/
Now I want to: 1) save upper case for inner HTML from tag abbr; 2) delete all similar element from the array (as MABs).
I was trying to find the way to split the array by tag, but all that I've done is:
for(var i=0; i<allbold.length; i++){
labels[i] = allbold[i].innerHTML;
}
var searchTerm = ['abbr'];
var abbr = [];
var keywordIndex;
$.each(labels, function(i) {
$.each(searchTerm, function(j) {
var rSearchTerm = new RegExp('\\b' + searchTerm[j] + '\\b','i');
if (labels[i].match(rSearchTerm)) {
keywordIndex = i;
for(var j=0; j<labels.length; j++){
abbr[i] = labels[i];
}
}
});
});

Vanilla JS solution (no library required, see jsFiddle):
var allbold = document.querySelectorAll("b"),
words = document.querySelector("#words"),
labels = {}, i, word, keys, label;
// first, collect all words in an object (this eliminates duplicates)
for(i = 0; i < allbold.length; i++) {
word = allbold[i].textContent.trim();
if (word === 'Labels:') continue;
labels[word.toLowerCase()] = word;
}
// then sort the object keys and output the words in original case
keys = Object.keys(labels).sort();
for(i = 0; i < keys.length; i++){
label = document.createTextNode("SPAN");
label.textContent = labels[keys[i]];
words.appendChild(label);
// add a comma if necessary
if (i < keys.length - 1) {
words.appendChild(document.createTextNode(", "));
}
}
with one helper:
String.prototype.trim = function () {
return this.replace(/^\s+|\s+$/g, "");
};
jQuery solution (see jsFiddle):
$(".content b").map(function () {
return $("<span>", {text: $.trim(this.textContent)})[0];
}).unique(function () {
return lCaseText(this);
}).sort(function (a, b) {
return lCaseText(a) < lCaseText(b) ? -1 : 1;
}).appendTo("#words");
with two helpers:
$.fn.extend({
unique: function (keyFunc) {
var keys = {};
return this.map(function () {
var key = keyFunc.apply(this);
if (!keys.hasOwnProperty(key)) {
keys[key] = true;
return this;
}
});
}
});
function lCaseText(element) {
return element.textContent.toLowerCase();
}

use the mapping element Is THIS FIDDLE for all upper case else this fiddle after your comment what you need
var maplabels = [];
for(var i=0; i<allbold.length; i++){
if (allbold[i].innerHTML != "Labels:") {
if(maplabels.indexOf(allbold[i].innerHTML) == -1){
maplabels.push(allbold[i].innerHTML);
labels.push('<i>' + allbold[i].innerHTML.toUpperCase() + '</i>');
}
}
}

display the recursion line by line

I am trying to make a function in javascript that would expand/split a string with dashes and show the process ( line by line ) using recursion.
for example, the string "anna" would become:
expand("anna") = expand("an")+"---"+expand("na") ->
"a"+"---"+"n"+"---"+"n"+"---"+"a"
and the desired output would be:
anna
an---na
a---n---n---a
I have achieved doing the following so far (I know it might not be the solution I am looking):
expand("anna") = an+"---"+expand("na")
= an+"---"+n+"---"+expand("a");
= an+"---"+n+"---+"a"
the output I am getting is:
an---n---a
I can't seem to concatenate the head though to do the first example.
My javascript function of expand is as follows:
function expand(word) {
if (word.length<=1) {
return word;
} else {
mid = word.length/2;
return word.substr(0,mid) + " " + expand(word.substr(mid,word.length));
}
}
document.write(expand("anna"));
I would need some tips to do this, otherwise (if it's the wrong stackexchange forum), please guide me where to post it.

this is my crazy attempt
var Word = function(str) {
this.isSplitable = function() {
return str.length > 1;
}
this.split = function() {
var p = Math.floor(str.length / 2);
return [
new Word(str.substr(0,p)),
new Word(str.substr(p,p+1))
];
}
this.toString = function() {
return str;
}
}
var expand = function(words) {
var nwords = [];
var do_recur = false;
words.forEach(function(word){
if(word.isSplitable()) {
var splitted = word.split();
nwords.push(splitted[0]);
nwords.push(splitted[1]);
do_recur = true;
}else{
nwords.push(word);
}
});
var result = [];
nwords.forEach(function(word){
result.push( word.toString() );
});
var result = result.join("--") + "<br/>";
if(do_recur) {
return result + expand(nwords);
}else{
return "";
}
}
document.write( expand([new Word("anna")]) );

This is what you need
expand = function(word) {
return [].map.call(word, function(x) {return x+'---'}).join('')
};
The joy of functional programming.
And with added code to deal with last character:
function expand(word) {
return [].map.call(word, function(x, idx) {
if (idx < word.length - 1)
return x+'---';
else return x
}).join('')
}

As I said that it is impossible to display the "process" steps of recursion while using recursion, here is a workaround that will output your desired steps:
var levels = [];
function expand(word, level) {
if (typeof level === 'undefined') {
level = 0;
}
if (!levels[level]) {
levels[level] = [];
}
levels[level].push(word);
if (word.length <= 1) {
return word;
} else {
var mid = Math.ceil(word.length/2);
return expand(word.substr(0, mid), level+1) + '---' + expand(word.substr(mid), level+1);
}
}
expand('anna');
for (var i = 0; i < levels.length; i++) {
console.log(levels[i].join('---'));
}

to see all steps the best that I whold do is:
function expand(word) {
if (word.length<=1) {
return word;
} else {
var mid = word.length/2;
var str1 = word.substr(0,mid);
var str2 = word.substr(mid,word.length);
document.write(str1 + "---" + str2 + "<br></br>");
return expand(str1) + "---" + expand(str2);
}
}
document.write(expand("anna"));

You have to return the two parts of the string:
function expand(word) {
output="";
if (word.length<=1) {
output+=word;
return output;
} else
{
var mid = word.length/2;
output+=word.substr(0,mid)+"---"+word.substr(mid)+" \n";//this line will show the steps.
output+=expand(word.substr(0,mid))+"---"+expand(word.substr(mid,word.length-1))+" \n";
return output;
}
}
console.log(expand("anna"));
Edit:
I added the output var and in every loop I concatenate the new output to it.
It should do the trick.

Hope the problem is in your first part. According to your algorithm, you are splitting your string anna in to two parts,
an & na
so you need to expand both parts until the part length is less than or equal to one. so your required function is the below one.
function expand(word) {
if (word.length<=1) {
return word;
} else {
mid = word.length/2;
return expand(word.substr(0,mid)) + " --- " + expand(word.substr(mid,word.length));
}
}
document.write(expand("anna"));

String modification issue in JS

I have a string like "word_count". How can I transform it to "WordCount" in an elegant way using JavaScript? My decision seems too complicated to me. I'll be very grateful for your help.

function titleCase(str)
{
return str.split("_")
.map(function (s) { return s.charAt(0).toUpperCase() + s.slice(1); })
.join("");
}

Take a look at this. I don't want to just copy paste everything here, but it seems to be just what you're looking for.
Here is the function modified to fit your request:
String.prototype.toCamel = function(){
return this.replace(/((^|\_)[a-z])/g, function($1){
return $1.toUpperCase().replace('_','');});
};
And here it is in action.

You can use a regular expression to match either a letter at the start of the string or a letter after an underscore, and use a callback to turn the letter into uppercase:
s = s.replace(/(?:^|_)([a-z])/g, function(m, g){
return g.toUpperCase();
});
Demo: http://jsfiddle.net/Guffa/ByU6P/

Simple, like this:
var string = "word_count".split("_");
for(var i = 0; i<string.length;i++) {
string[i] = string[i].charAt(0).toUpperCase() + string[i].substr(1);
}
var myNiceString = string.join();
If you want to add it to the String object, you can do this:
String.prototype.titleCase = function() {
var split = this.split("_");
for(var i = 0; i<split.length;i++) {
split[i] = split[i].charAt(0).toUpperCase() + split[i].substr(1);
}
return split.join("");
}
You'd call it like "word_count".titleCase();

You can use a function like the following:
var Pascalize = function(word) {
var x = word;
result = '';
if(-1 != word.indexOf('_')) {
x = word.split('_');
for(var i=0;i<x.length;i++) {
result += x[i].substr(0, 1).toUpperCase() + x[i].substr(1);
}
}
if('' == result) { result = word; }
return result;
};
var PascalCaseString = Pascalize("this_is_a_test");
// PascalCaseString value is now 'ThisIsATest'
Here's a working example

var str = "word_count";
var re = /\b(.)([^_]+)_(.)/;
var newWord = str.replace(re, function(m,f,t,l){ return f.toUpperCase() + t + l.toUpperCase();})
console.log(newWord);

Using jQuery, you could do the following:
var result = '';
$.each('word_count'.split('_'), function(idx,elem){
result = result + elem.substr(0,1).toUpperCase() + elem.substr(1);
});

New version (works with any amount of _):
function fixString(sString) {
var aWords = sString.split("_"),
sResults = "";
for (var i in aWords)
sResults += aWords[i].charAt(0).toUpperCase() + aWords[i].slice(1);
return sResults;
}
The compressed form:
function fixString(c){var d=c.split("_"),a="";for(var b in d){a+=d[b].charAt(0).toUpperCase()+d[b].slice(1)}return a};
Old:
function fixString(sString) {
return sString.replace(/(.*)_(.*)/, function(sWhole, $1, $2, sWTF) {
return ucfirst($1) + ucfirst($2);
} )
function ucfirst (str) {
str += '';
var f = str.charAt(0).toUpperCase();
return f + str.substr(1);
}
}
... or the compressed version:
function fixString(b){return b.replace(/(.*)_(.*)/,function(e,c,f,d){return a(c)+a(f)});function a(d){d+="";var c=d.charAt(0).toUpperCase();return c+d.substr(1)}};
Of course, this is used like fixString("word_count") which results in your desired WordCount.

I've looked at all the answer and none did precisely what I wanted. I wanted an idempotent function which converted to camelCase (not PascalCase) and I liked the String prototype extension approach (although obviously this isn't always the best medicine).
Anyway, here's where I ended up:
String.prototype.camelize = function(){
var pascalCase = this.replace(/((^|\_)[a-z])/g, function($1){
return $1.toUpperCase().replace('_','');
});
return pascalCase.charAt(0).toLowerCase() + this.slice(1);
};

var aStringLike = "word_count";
// magic follows
aStringLike = "WordCount";