Develop Reference

How to pick only Capital characters from the string?

I am try to pick capital characters from the string with the help of a function and for loop but i can't figure out how i can do it i try using toUpperCase as you see it in the code but it is not work any idea how i can do it ?
function onlyCapitalLetters(cap){
var string = "";
for(var i = 0; i < cap.length; i++){
if(cap[i] === cap.toUpperCase()){
string += cap[i];
}
}
return string;
}
onlyCapitalLetters("Apple");

You can try the regex, with String.prototype.match to return capital letters only:
function onlyCapitalLetters(cap){
return cap.match(/[A-Z]/g, "").join(''); // join the array to return a string
}
console.log(onlyCapitalLetters("Apple"));
console.log(onlyCapitalLetters("BUTTerfly"));
console.log(onlyCapitalLetters("LION"));

Can you try like this
function findUpcase(value){
input = value
data = ""
input.split("").map(res => {
if(res == res.toUpperCase()){
data = data+ res
}
})
return data
}
console.log( findUpcase("MyNameIsVelu") );
//'MNIV'

As noted in comments you need to change cap.toUpperCase() to cap[i].toUpperCase().
But you can do it with just one replace:
console.log('Apple Orange'.replace(/[^A-Z]/g, ""));

It is possible to use replace method with Regex to eliminate numbers and letters written in lowercase:
let str = 'T1eeeEeeeSssssssTttttt';
let upperCase = str.replace(/[a-z0-1]/g, '')
console.log(upperCase);

Please Use Below code to get Capital letter of the sentence :
Demo Code
var str = 'i am a Web developer Student';
var sL = str.length;
var i = 0;
for (; i < sL; i++) {
if (str.charAt(i) != " ") {
if (str.charAt(i) === str.charAt(i).toUpperCase()){
console.log(str.charAt(i));
break;
}
}
}

What is wrong with the logic of my character changing function?

I've tried to create a character changing function for strings, it suppose to change all the "-" to "_", and it only does it for the first character and leaves the rest. If someone could explain it would be grate.
function kebabToSnake(str) {
var idNum = str.length;
for(var i = 0; i <= idNum; i++) {
var nStr = str.replace("-", "_");
}
return nStr;
}

var nStr = str.replace("-", "_");
So, on each iteration, you're replacing the first found - character in the original string, not the string that you've already replaced characters from already. You can either call .replace on just one variable that you reassign:
function kebabToSnake(str) {
var idNum = str.length;
for(var i = 0; i < idNum; i++) {
str = str.replace("-", "_");
}
return str;
}
console.log(kebabToSnake('ab-cd-ef'));
(note that you should iterate from 0 to str.length - 1, not from 0 to str.length)
Or, much, much more elegantly, use a global regular expression:
function kebabToSnake(str) {
return str.replace(/-/g, '_');
}
console.log(kebabToSnake('ab-cd-ef'));

How can I write a function that will format a camel cased string to have spaces?

I need to write a function that will take a string 'camelCased' and then format it to add spaces to it: 'camel Cased'.

You can use regex to split on capitals and then rejoin with space:
.split(/(?=[A-Z])/).join(' ')
let myStrings = ['myString','myTestString'];
function myFormat(string){
return string.split(/(?=[A-Z])/).join(' ');
}
console.log(myFormat(myStrings[0]));
console.log(myFormat(myStrings[1]));

You could replace upper case letters with a leading space.
var string = 'camelCased';
console.log(string.replace(/[A-Z]/g, ' $&'));

I think this will Help
function replaceCamelCase()
{
var op="";
for(int i = 0; i < input.Length; i++)
{
if(isUpper(input.charAt(i))
{
op+=" "+input.charAt(i);
}
op+=input.charAt(i);
}
alert(op);
}
function isUpper(){
if (character == character.toUpperCase())
{
return true;
}
return false;
}

Javascript: Cut string after last specific character

I'm doing some Javascript to cut strings into 140 characters, without breaking words and stuff, but now i want the text so have some sense. so i would like if you find a character (just like ., , :, ;, etc) and if the string is>110 characters and <140 then slice it, so the text has more sense. Here is what i have done:
where texto means text, longitud means length, and arrayDeTextos means ArrayText.
Thank you.
//function to cut strings
function textToCut(texto, longitud){
if(texto.length<longitud) return texto;
else {
var cortado=texto.substring(0,longitud).split(' ');
texto='';
for(key in cortado){
if(key<(cortado.length-1)){
texto+=cortado[key]+' ';
if(texto.length>110 && texto.length<140) {
alert(texto);
}
}
}
}
return texto;
}
function textToCutArray(texto, longitud){
var arrayDeTextos=[];
var i=-1;
do{
i++;
arrayDeTextos.push(textToCut(texto, longitud));
texto=texto.replace(arrayDeTextos[i],'');
}while(arrayDeTextos[i].length!=0)
arrayDeTextos.push(texto);
for(key in arrayDeTextos){
if(arrayDeTextos[key].length==0){
delete arrayDeTextos[key];
}
}
return arrayDeTextos;
}

Break the string into sentences, then check the length of the final string before appending each sentence.
var str = "Test Sentence. Test Sentence";
var arr = str.split(/[.,;:]/) //create an array of sentences delimited by .,;:
var final_str = ''
for (var s in arr) {
if (final_str.length == 0) {
final_str += arr[s];
} else if (final_str.length + s.length < 140) {
final_str += arr[s];
}
}
alert(final_str); // should have as many full sentences as possible less than 140 characters.

I think Martin Konecny's solution doesn't work well because it excludes the delimiter and so removes lots of sense from the text.
This is my solution:
var arrTextChunks = text.split(/([,:\?!.;])/g),
finalText = "",
finalTextLength = 0;
for(var i = 0; i < arrTextChunks.length; i += 2) {
if(finalTextLength + arrTextChunks[i].length + 1 < 140) {
finalText += arrTextChunks[i] + arrTextChunks[i + 1];
finalTextLength += arrTextChunks[i].length;
} else if(finalTextLength > 110) {
break;
}
}
http://jsfiddle.net/Whre/3or7j50q/3/
I'm aware of the fact that the i += 2 part does only make sense for "common" usages of punctuation (a single dot, colon etc.) and nothing like "hi!!!?!?1!1!".

Should be a bit more effective without regex splits.
var truncate = function (str, maxLen, delims) {
str = str.substring(0, maxLen);
return str.substring(0, Math.max.apply(null, delims.map(function (s) {
return str.lastIndexOf(s);
})));
};

Try this regex, you can see how it works here: http://regexper.com/#%5E(%5Cr%5Cn%7C.)%7B1%2C140%7D%5Cb
str.match(/^(\r\n|.){1,140}\b/g).join('')

How do I enhance slugify to handle Camel Case?

I'd like to write a JavaScript function to slugify a string, with one more requirement: handle Camel Case. For example, thisIsCamelCase would become this-is-camel-case.
How do I modify a function like this to do so?
EDIT
Added full, answered example.

You just need to add one line of code to what you posted
str = str.replace(/[A-Z]/g, function(s){ return "-" + s; });
This brings the remaining code to be
function string_to_slug(str) {
str = str.replace(/^\s+|\s+$/g, ''); // trim
str = str.replace(/[A-Z]/g, function(s){ return "-" + s; }); // camel case handling
str = str.toLowerCase();
// remove accents, swap ñ for n, etc
var from = "àáäâèéëêìíïîòóöôùúüûñç·/_,:;",
to = "aaaaeeeeiiiioooouuuunc------";
for (var i=0, l=from.length ; i<l ; i++) {
str = str.replace(from[i], to[i]);
}
str = str.replace(/[^a-z0-9 -]/g, '') // remove invalid chars
.replace(/\s+/g, '-') // collapse whitespace and replace by -
.replace(/-+/g, '-'); // collapse dashes
return str;
}
Edit :: I also deleted the useless new RegExp logic too.
Edit :: Added 'g' to find all caps, not just the first one.

This will help you!
var strings = 'toDo';
var i=0;
var ch='';
while (i < strings.length){
character = strings.charAt(i);
if (character == character.toUpperCase()) {
//alert ('upper case true' + character);
character = "-" + character.toLowerCase();
}
i++;
ch += character;
}
//to-do
alert(ch);

Try using:
str=str.toLowerCase() before or after the slugification.