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JavaScript-Creating a Function to capitalise the first letter of a string [duplicate]

This question already has answers here:
Convert string to Pascal Case (aka UpperCamelCase) in Javascript
(5 answers)
Closed 2 years ago.
I'm having trouble in creating a function to capitalise the first letter of a string. I can capitalise the string when I enter words in lowercase, but not in uppercase. I really appreciate some assistance with this problem, please see my script below:
function captialise(str) {
str = prompt("Enter a string");
console.log(str[0].toUpperCase() + str.substring(1))
}
captialise();

Uppercase the first character, lowercase the rest. The snippet uses a bit more modern scripting (the function uses a template literal)
const capitalize = str => str.slice
? `${str.slice(0,1).toUpperCase()}${str.slice(1).toLowerCase()}`
: str;
const str1 = `someSTRING`;
const str2 = `someotherstring`;
const str3 = `s23omeotherstring`;
const str4 = prompt('enter something');
console.log(capitalize(str1));
console.log(capitalize(str2));
console.log(capitalize(str3));
console.log(capitalize(str4));

There are many ways to do it, and I believe it was asked a lot of time here before,
This one is with one line:
function captialise(str) {
str = prompt("Enter a string");
console.log(`${str[0].toUpperCase()}${str.substring(1).toLowerCase()}`);
}
captialise();

The logical problem is that you're capitalising the first part yes, but you're NOT lowering the other parts
function captialise(str) {
str = prompt("Enter a string");
console.log(str[0].toUpperCase() + str.substring(1).toLowerCase())
}
captialise();

It is recommended to have a function return what you name it.
You need to lowerCase the rest of the string too and I would test you have a string in the first place
I chose to use + instead of template literals since it is easier to read in this simple case
const captialise = str => str && typeof str === "string" ?
str.slice(0,1).toUpperCase() + str.slice(1).toLowerCase() :
str;
console.log(
captialise(prompt("Enter a string"))
)

Using Regex as conditional in Javascript [duplicate]

This question already has answers here:
How to check if character is a letter in Javascript?
(17 answers)
Closed 3 years ago.
Hello I am having trouble trying to use Regex to check if each character in string is an alphabet.
First let me introduce the problem itself.
There is a string mixed with special chars and alphabets and suppose to return the number of alphabets only.
My code/pseudo code for problem is :
//Create var to hold count;
var count = 0;
//Loop thru str
for(let char of str){
//Check if char is a alphabet
***if(char === /[A-Za-z]/gi){***
//if so add to count
count ++;
}
//return count;
return count;
}
How can I use Regex in a conditional statement to check if each char is an alphabet????
Please help!

const pattern = /[a-z]/i
const result = [...'Abc1'].reduce((count,c) => pattern.test(c) ? count+1 : count, 0)
console.log(result) // 3

Javascript check for a whole word in a unicode string [duplicate]

This question already has answers here:
Find words from array in string, whole words only (with hebrew characters)
(2 answers)
Match any non-word character (excluding diacritics)
(1 answer)
How to ban words with diacritics using a blacklist array and regex?
(5 answers)
Closed 3 years ago.
What is the correct way to check for a whole word in a unicode string in Javascript.
This works for ASCII only:
var strHasWord = function(word, str){
return str.match(new RegExp("\\b" + word + "\\b")) != null;
};
I tried XRegExp as follows but this does not work either.
var strHasWord = function(word, str){
// look for separators/punctuation characters or if the word is the first or the last in the string
var re = XRegExp("(\\p{Z}|\\p{P}|^)" + word + "(\\p{Z}|\\p{P}|$)");
return re.test(str);
//return str.match(re);
}
Any suggestions. Thanks.
EDIT 1
The following seems to do the trick.
var function strHasWord = function(word, str){
var re = RegExp("(\\p{Z}|\\p{P}|^)" + word + "(\\p{Z}|\\p{P}|$)", "u");
return str.match(re) != null;
//return re.test(str);
}

Capitalizing certain strings in an array [duplicate]

This question already has answers here:
Convert string to Title Case with JavaScript
(68 answers)
How do I make the first letter of a string uppercase in JavaScript?
(96 answers)
How can I capitalize the first letter of each word in a string using JavaScript?
(46 answers)
Closed 4 years ago.
I basically want to capitalize the first letter in every word in a sentence, assuming that str is all lowercase. So here, I tried to split the string, letter by letter, then by using for loop, I would capitalize whatever the letter that's after a space. Here's my code and could you please point out where I coded wrong? Thank you.
function titleCase(str) {
var strArray = str.split('');
strArray[0].toUpperCase();
for (i=0; i<strArray.length;i++){
if (strArray[i]===" "){
strArray[i+1].toUpperCase();
}
}
return strArray.join('');
}

You need to assign the values:
function titleCase(str) {
var strArray = str.split('');
strArray[0] = strArray[0].toUpperCase();
for (i=0; i<strArray.length;i++){
if (strArray[i]===" "){
strArray[i+1] = strArray[i+1].toUpperCase();
}
}
return strArray.join('');
}

You can try following
function titleCase(str) {
var strArray = str.split(' ');
for (i=0; i<strArray.length;i++){
strArray[i] = strArray[i].charAt(0).toUpperCase() + strArray[i].slice(1);
}
return strArray.join(' ');
}
console.log(titleCase("i am a sentence"));

Basic Javascript Algorithm [duplicate]

This question already has answers here:
Capitalize words in string [duplicate]
(21 answers)
Closed 7 years ago.
What to do - Capitalize the first letter of the words in a sentence.
So, I solved it and was wondering is there any way to do it without making it an array with .split().
What I tried without turning it into a array -
The logic - First, turn everything into lowercase. Then scan the sentence with a for loop, if you find a space, capitalize the next character.
function titleCase(str) {
str = str.toLowerCase();
for(i=0;i<str.length;i++) {
if(str[i]===" ") {
str = str.charAt[i+1].toUpperCase();
return str;
}
}
}
titleCase("I'm a little tea pot", "");
That code doesn't even run.

I just used split() and replace to do that. You can have a look at my code.
function titleCase (str)
{
str = str.split(' ');
for(var i=0;i<str.length;i++)
{
str[i] = str[i].replace(str[i][0],str[i][0].toUpperCase())
}
return str.join(' ');
}
var mainString ="i am strong!";
titleCase(mainString);

Here is one using replace + with a regex:
/**
* #summary Uppercase the first letter in a string.
* #returns {string}
*/
function uppercaseFirstLetters(string) {
return string.replace(/[a-zA-Z]*/g, function(match) {
return match.charAt(0).toUpperCase() + match.substr(1).toLowerCase();
})
}