Develop Reference

Writing function that returns string but with all five or more letters reversed JS

first time posting. I'm writing a function in js that reverses words with more than 5 characters in a given string. It works, but I think it is adding extra "space" strings that it doesn't need if the string inputted is only one word. I know I have too many variables and there is a way better way to do this. I'm pretty new to this, but anything helps. Thanks!
const exString = "Hey fellow warriors"
function spinWords(string){
let newWord = string.split(' ');
let fiveWord = "";
let lessWord = "";
for(i=0; i<newWord.length;i++){
if(newWord[i].length >=5){
fiveWord += newWord[i].split('').reverse() + ' ';
}
else{
lessWord += newWord[i]
}
}
newFiveWord = fiveWord.replace(/,/g,'');
return lessWord + ' ' + newFiveWord
}
console.log(spinWords(exString));

const spinWords = str => str
.split(' ')
.map(word => word.length >= 5
? [...word].reverse().join('')
: word)
.join(' ')
console.log(spinWords("Hey fellow warriors"))
Turn the string into an array of words
Modify each word. If 5+ letters: [..word] turns the string into an array of letters ('hi' > ['h', 'i']). Then reverse the array, and turn the letters back into one string.
Undo step one by turning the array into one string.

function reversedText() {
let text = prompt("Enter text");
const words = text?.split(" ");
const newText = words.map((word) => {
if (word.length >= 5) {
return (word.split("").reverse().join(""));
}
return word;
});
if (newText.length > 0) {
return newText.filter(notNull).join(" ");
} else {
return 'Your sentence have words which have length less than 5';
}
}
function notNull(value) {
return value != null
}
console.log(reversedText());

Replace consecutive white spaces between words with one hyphen

The question is from freecodecamp Link
Fill in the urlSlug function so it converts a string title and returns the hyphenated version for the URL. You can use any of the methods covered in this section, and don't use replace. Here are the requirements:
The input is a string with spaces and title-cased words
The output is a string with the spaces between words replaced by a
hyphen (-)
The output should be all lower-cased letters
The output should not have any spaces
// the global variable
var globalTitle = " Winter Is Coming";
function urlSlug(title) {
let toArr = title.split("");
let newArr = toArr.map(a=> {
if(a==" "){
a= "-";
}
return a.toLowerCase();
} );
if(newArr[0] == "-"){
newArr.splice(0,1);
}
let finalArr = newArr.join("");
return finalArr;
}
// Add your code above this line
var winterComing = urlSlug(globalTitle); // Should be "winter-is-coming"
console.log(urlSlug(globalTitle));
Right now I have not been able to solve how I could get rid of the extra hyphen from the output.
I'm not supposed to use replace.

You could do this easily using trim() and a simple regex:
var globalTitle = " Winter Is Coming Now ";
var slug = globalTitle.trim().replace(/[ ]+/g, '-').toLowerCase();
console.log(slug);
[ ]+ ensures that any number of spaces (1 or more) gets replaced with a minus sign once.
If for some reason you can't use replace, you could use Array.filter() like so:
var title = " Winter Is Coming Now ";
var slug = title.split(" ").filter(word => word.length > 0).join("-").toLowerCase();
console.log(slug);

I was working on it till now , Haven't looked at the answers.
But I solved it this way. Might be inefficient.
// the global variable
var globalTitle = "Winter Is Coming";
function urlSlug(title) {
let toArr = title.split("");
let newArr = toArr.map(a=> {
if(a==" "){
a= "-";
}
return a.toLowerCase();
} );
if(newArr[0] == "-"){
newArr.splice(0,1);
}
for(let i=0;i<newArr.length;i++){
if(newArr[i-1]=="-"&& newArr[i]=="-")
{
newArr.splice(i,1,"");
}
}
let finalArr = newArr.join("");
return finalArr;
}
var winterComing = urlSlug(globalTitle); // Should be "winter-is-coming"
console.log(urlSlug(globalTitle));

Another option would be to continue your thought of split() and then use reduce to reduce the elements of the array to a single output:
var globalTitle = " Winter Is Coming";
function urlSlug(title) {
let split = title.split(' ');
return split.reduce((accumulator, currentValue, index) => {
if (currentValue.length > 0) {
accumulator += currentValue.toLowerCase();
accumulator += (index < split.length - 1) ? '-' : '';
}
return accumulator;
});
}
console.log(urlSlug(globalTitle));

Remove space without using string method trim

How can I remove all the left space without removing between & the right space of the string? And also when I changed the value of str the result will be the same. Only the left space will be removed.
function trimLeftSpace() {
var str = " Angry Bird ";
var splitTrim = str.split('');
var trimStr = "";
for (var index = 0; index < splitTrim.length; index++) { //trim left space
if(splitTrim[index] != " ") {
trimStr += str[index];
}
}
return trimStr;
}

Your current solution creates a new string which contains all the non-space characters of the original string, you need to stop looking for spaces as soon as you find a non-space character. Here is an example:
function trimLeftSpace(str) {
var doneTrimming = false
var ret = ""
for (var index = 0; index < str.length; index++) {
if(str[index] !== ' '){
doneTrimming = true
}
if(doneTrimming){
ret += str[index]
}
}
return ret;
}
var result = trimLeftSpace(" Angry Bird ");
console.log("|"+result+"|");

To trim the beginning of the string, use a simple regex to replace the whitespaces in the beginning of the string:
var str = " Angry Bird ";
function trimLeftSpace(str) {
return str.replace(/^\s+/, '');
}
console.log('"' + trimLeftSpace(str) + '"');
Or just use .trimStart():
var str = " Angry Bird ";
function trimLeftSpace(str) {
return str.trimStart();
}
console.log('"' + trimLeftSpace(str) + '"');

You could try a regex replacement:
var str = " Angry Bird ";
str = str.replace( new RegExp("^\\s+", "gm"),"");
console.log('"' + str + '"');

This will remove all whitespace on the left of the string:
function trimLeftSpace(str) {
var result = "";
for(var i = 0; i < str.length; i++) {
if(str[i] != " ") {
return str.slice(i);
break;
} else {
result += str[i];
}
}
return result;
}
console.log(trimLeftSpace(" Angry Birds Angry Birds"));

Try this
function trimLeftSpace(str) {
return str.replace(/\s+$/, '')
}
var result = trimLeftSpace(" Angry Bird ");
console.log("|"+result+"|");

If you want to use a function instead of regex solutions from the other answers, then make a function that looks for the first non-space character, then use slice to cut only the part of the string that's after it:
function customTrim(str) {
for(var i = 0; i < str.length; i++) {
if(str.charAt(i) !== " ") {
return str.slice(i);
}
}
}
var res = customTrim(" Snake Shot ");
console.log('"' + res + '"');
Notes:
This only looks for spaces ' '. If you want to look for tabs '\t', newlines '\n', ... then just add them to the if test (sperate them with &&).
If an empty or space-only strings are passed, then undefined is returned, if you don't want that then just return an empty string at the bottom of the function to make it the default return value.

You could try a regex replacement:
let variable = "hello world";
let removeRegex = /^\s+|\s+$/g;
let removeSpace = variable.replace(removeRegex,"");
console.log(removeSpace);

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 to add a space in a specific index of a string? [duplicate]

How can I insert a string at a specific index of another string?
var txt1 = "foo baz"
Suppose I want to insert "bar " after the "foo" how can I achieve that?
I thought of substring(), but there must be a simpler more straight forward way.

Inserting at a specific index (rather than, say, at the first space character) has to use string slicing/substring:
var txt2 = txt1.slice(0, 3) + "bar" + txt1.slice(3);

You could prototype your own splice() into String.
Polyfill
if (!String.prototype.splice) {
/**
* {JSDoc}
*
* The splice() method changes the content of a string by removing a range of
* characters and/or adding new characters.
*
* #this {String}
* #param {number} start Index at which to start changing the string.
* #param {number} delCount An integer indicating the number of old chars to remove.
* #param {string} newSubStr The String that is spliced in.
* #return {string} A new string with the spliced substring.
*/
String.prototype.splice = function(start, delCount, newSubStr) {
return this.slice(0, start) + newSubStr + this.slice(start + Math.abs(delCount));
};
}
Example
String.prototype.splice = function(idx, rem, str) {
return this.slice(0, idx) + str + this.slice(idx + Math.abs(rem));
};
var result = "foo baz".splice(4, 0, "bar ");
document.body.innerHTML = result; // "foo bar baz"
EDIT: Modified it to ensure that rem is an absolute value.

Here is a method I wrote that behaves like all other programming languages:
String.prototype.insert = function(index, string) {
if (index > 0)
{
return this.substring(0, index) + string + this.substring(index, this.length);
}
return string + this;
};
//Example of use:
var something = "How you?";
something = something.insert(3, " are");
console.log(something)
Reference:
http://coderamblings.wordpress.com/2012/07/09/insert-a-string-at-a-specific-index/

Just make the following function:
function insert(str, index, value) {
return str.substr(0, index) + value + str.substr(index);
}
and then use it like that:
alert(insert("foo baz", 4, "bar "));
Output: foo bar baz
It behaves exactly, like the C# (Sharp) String.Insert(int startIndex, string value).
NOTE: This insert function inserts the string value (third parameter) before the specified integer index (second parameter) in the string str (first parameter), and then returns the new string without changing str!

UPDATE 2016: Here is another just-for-fun (but more serious!) prototype function based on one-liner RegExp approach (with prepend support on undefined or negative index):
/**
* Insert `what` to string at position `index`.
*/
String.prototype.insert = function(what, index) {
return index > 0
? this.replace(new RegExp('.{' + index + '}'), '$&' + what)
: what + this;
};
console.log( 'foo baz'.insert('bar ', 4) ); // "foo bar baz"
console.log( 'foo baz'.insert('bar ') ); // "bar foo baz"
Previous (back to 2012) just-for-fun solution:
var index = 4,
what = 'bar ';
'foo baz'.replace(/./g, function(v, i) {
return i === index - 1 ? v + what : v;
}); // "foo bar baz"

This is basically doing what #Base33 is doing except I'm also giving the option of using a negative index to count from the end. Kind of like the substr method allows.
// use a negative index to insert relative to the end of the string.
String.prototype.insert = function (index, string) {
var ind = index < 0 ? this.length + index : index;
return this.substring(0, ind) + string + this.substr(ind);
};
Example:
Let's say you have full size images using a naming convention but can't update the data to also provide thumbnail urls.
var url = '/images/myimage.jpg';
var thumb = url.insert(-4, '_thm');
// result: '/images/myimage_thm.jpg'

If anyone is looking for a way to insert text at multiple indices in a string, try this out:
String.prototype.insertTextAtIndices = function(text) {
return this.replace(/./g, function(character, index) {
return text[index] ? text[index] + character : character;
});
};
For example, you can use this to insert <span> tags at certain offsets in a string:
var text = {
6: "<span>",
11: "</span>"
};
"Hello world!".insertTextAtIndices(text); // returns "Hello <span>world</span>!"

Instantiate an array from the string
Use Array#splice
Stringify again using Array#join
The benefits of this approach are two-fold:
Simple
Unicode code point compliant
const pair = Array.from('USDGBP')
pair.splice(3, 0, '/')
console.log(pair.join(''))

Given your current example you could achieve the result by either
var txt2 = txt1.split(' ').join(' bar ')
or
var txt2 = txt1.replace(' ', ' bar ');
but given that you can make such assumptions, you might as well skip directly to Gullen's example.
In a situation where you really can't make any assumptions other than character index-based, then I really would go for a substring solution.

my_string = "hello world";
my_insert = " dear";
my_insert_location = 5;
my_string = my_string.split('');
my_string.splice( my_insert_location , 0, my_insert );
my_string = my_string.join('');
https://jsfiddle.net/gaby_de_wilde/wz69nw9k/

I know this is an old thread, however, here is a really effective approach.
var tn = document.createTextNode("I am just to help")
t.insertData(10, "trying");
What's great about this is that it coerces the node content. So if this node were already on the DOM, you wouldn't need to use any query selectors or update the innerText. The changes would reflect due to its binding.
Were you to need a string, simply access the node's text content property.
tn.textContent
#=> "I am just trying to help"

You can do it easily with regexp in one line of code
const str = 'Hello RegExp!';
const index = 6;
const insert = 'Lovely ';
//'Hello RegExp!'.replace(/^(.{6})(.)/, `$1Lovely $2`);
const res = str.replace(new RegExp(`^(.{${index}})(.)`), `$1${insert}$2`);
console.log(res);
"Hello Lovely RegExp!"

Well, we can use both the substring and slice method.
String.prototype.customSplice = function (index, absIndex, string) {
return this.slice(0, index) + string+ this.slice(index + Math.abs(absIndex));
};
String.prototype.replaceString = function (index, string) {
if (index > 0)
return this.substring(0, index) + string + this.substr(index);
return string + this;
};
console.log('Hello Developers'.customSplice(6,0,'Stack ')) // Hello Stack Developers
console.log('Hello Developers'.replaceString(6,'Stack ')) //// Hello Stack Developers
The only problem of a substring method is that it won't work with a negative index. It's always take string index from 0th position.

You can use Regular Expressions with a dynamic pattern.
var text = "something";
var output = " ";
var pattern = new RegExp("^\\s{"+text.length+"}");
var output.replace(pattern,text);
outputs:
"something "
This replaces text.length of whitespace characters at the beginning of the string output.
The RegExp means ^\ - beginning of a line \s any white space character, repeated {n} times, in this case text.length. Use \\ to \ escape backslashes when building this kind of patterns out of strings.

another solution, cut the string in 2 and put a string in between.
var str = jQuery('#selector').text();
var strlength = str.length;
strf = str.substr(0 , strlength - 5);
strb = str.substr(strlength - 5 , 5);
jQuery('#selector').html(strf + 'inserted' + strb);

Using slice
You can use slice(0,index) + str + slice(index). Or you can create a method for it.
String.prototype.insertAt = function(index,str){
return this.slice(0,index) + str + this.slice(index)
}
console.log("foo bar".insertAt(4,'baz ')) //foo baz bar
Splice method for Strings
You can split() the main string and add then use normal splice()
String.prototype.splice = function(index,del,...newStrs){
let str = this.split('');
str.splice(index,del,newStrs.join('') || '');
return str.join('');
}
var txt1 = "foo baz"
//inserting single string.
console.log(txt1.splice(4,0,"bar ")); //foo bar baz
//inserting multiple strings
console.log(txt1.splice(4,0,"bar ","bar2 ")); //foo bar bar2 baz
//removing letters
console.log(txt1.splice(1,2)) //f baz
//remving and inseting atm
console.log(txt1.splice(1,2," bar")) //f bar baz
Applying splice() at multiple indexes
The method takes an array of arrays each element of array representing a single splice().
String.prototype.splice = function(index,del,...newStrs){
let str = this.split('');
str.splice(index,del,newStrs.join('') || '');
return str.join('');
}
String.prototype.mulSplice = function(arr){
str = this
let dif = 0;
arr.forEach(x => {
x[2] === x[2] || [];
x[1] === x[1] || 0;
str = str.splice(x[0] + dif,x[1],...x[2]);
dif += x[2].join('').length - x[1];
})
return str;
}
let txt = "foo bar baz"
//Replacing the 'foo' and 'bar' with 'something1' ,'another'
console.log(txt.splice(0,3,'something'))
console.log(txt.mulSplice(
[
[0,3,["something1"]],
[4,3,["another"]]
]
))

I wanted to compare the method using substring and the method using slice from Base33 and user113716 respectively, to do that I wrote some code
also have a look at this performance comparison, substring, slice
The code I used creates huge strings and inserts the string "bar " multiple times into the huge string
if (!String.prototype.splice) {
/**
* {JSDoc}
*
* The splice() method changes the content of a string by removing a range of
* characters and/or adding new characters.
*
* #this {String}
* #param {number} start Index at which to start changing the string.
* #param {number} delCount An integer indicating the number of old chars to remove.
* #param {string} newSubStr The String that is spliced in.
* #return {string} A new string with the spliced substring.
*/
String.prototype.splice = function (start, delCount, newSubStr) {
return this.slice(0, start) + newSubStr + this.slice(start + Math.abs(delCount));
};
}
String.prototype.splice = function (idx, rem, str) {
return this.slice(0, idx) + str + this.slice(idx + Math.abs(rem));
};
String.prototype.insert = function (index, string) {
if (index > 0)
return this.substring(0, index) + string + this.substring(index, this.length);
return string + this;
};
function createString(size) {
var s = ""
for (var i = 0; i < size; i++) {
s += "Some String "
}
return s
}
function testSubStringPerformance(str, times) {
for (var i = 0; i < times; i++)
str.insert(4, "bar ")
}
function testSpliceStringPerformance(str, times) {
for (var i = 0; i < times; i++)
str.splice(4, 0, "bar ")
}
function doTests(repeatMax, sSizeMax) {
n = 1000
sSize = 1000
for (var i = 1; i <= repeatMax; i++) {
var repeatTimes = n * (10 * i)
for (var j = 1; j <= sSizeMax; j++) {
var actualStringSize = sSize * (10 * j)
var s1 = createString(actualStringSize)
var s2 = createString(actualStringSize)
var start = performance.now()
testSubStringPerformance(s1, repeatTimes)
var end = performance.now()
var subStrPerf = end - start
start = performance.now()
testSpliceStringPerformance(s2, repeatTimes)
end = performance.now()
var splicePerf = end - start
console.log(
"string size =", "Some String ".length * actualStringSize, "\n",
"repeat count = ", repeatTimes, "\n",
"splice performance = ", splicePerf, "\n",
"substring performance = ", subStrPerf, "\n",
"difference = ", splicePerf - subStrPerf // + = splice is faster, - = subStr is faster
)
}
}
}
doTests(1, 100)
The general difference in performance is marginal at best and both methods work just fine (even on strings of length ~~ 12000000)

Take the solution. I have written this code in an easy format:
const insertWord = (sentence,word,index) => {
var sliceWord = word.slice(""),output = [],join; // Slicing the input word and declaring other variables
var sliceSentence = sentence.slice(""); // Slicing the input sentence into each alphabets
for (var i = 0; i < sliceSentence.length; i++)
{
if (i === index)
{ // checking if index of array === input index
for (var j = 0; j < word.length; j++)
{ // if yes we'll insert the word
output.push(sliceWord[j]); // Condition is true we are inserting the word
}
output.push(" "); // providing a single space at the end of the word
}
output.push(sliceSentence[i]); // pushing the remaining elements present in an array
}
join = output.join(""); // converting an array to string
console.log(join)
return join;
}

Prototype should be the best approach as many mentioned. Make sure that prototype comes earlier than where it is used.
String.prototype.insert = function (x, str) {
return (x > 0) ? this.substring(0, x) + str + this.substr(x) : str + this;
};