CODEWITHSUNDEEP
javascript
Gerben Jacobs
Gerben Jacobs

Reputation: 4583

Get first letter of each word in a string, in JavaScript

How would you go around to collect the first letter of each word in a string, as in to receive an abbreviation?

Input: "Java Script Object Notation"

Output: "JSON"

Upvotes: 102

Views: 125880

Answers (20)

Aaron Taddiken
Aaron Taddiken

Reputation: 191

This is made very simple with ES6

string.split(' ').map(i => i.charAt(0)).join('')               // Inherit case of each letter
string.split(' ').map(i => i.charAt(0)).join('').toUpperCase() // Uppercase each letter
string.split(' ').map(i => i.charAt(0)).join('').toLowerCase() // lowercase each letter

.split(' ') creates an array of strings by splitting the original string at each space

.map(i => i.charAt(0)) takes character 0 from each string in the array

.join('') joins the array of 1-character string back together into a single string

Upvotes: 9

exaucae
exaucae

Reputation: 2655

It's important to trim the word before splitting it, otherwise, we'd lose some letters.

const getWordInitials = (word: string): string => {
  const bits = word.trim().split(' ');
  return bits
    .map((bit) => bit.charAt(0))
    .join('')
    .toUpperCase();
};

$ getWordInitials("Java Script Object Notation")

$ "JSON"

Upvotes: 4

user13026823
user13026823

Reputation:

Try This Function

const createUserName = function (name) {
const username = name
    .toLowerCase()
    .split(' ')
    .map((elem) => elem[0])
    .join('');

    return username;
};

console.log(createUserName('Anisul Haque Bhuiyan'));

Upvotes: 0

Sinh Nguyễn Đức
Sinh Nguyễn Đức

Reputation: 711

In ES6:

function getFirstCharacters(str) {
  let result = [];

  str.split(' ').map(word => word.charAt(0) != '' ? result.push(word.charAt(0)) : '');
  
  return result;
}

const str1 = "Hello4 World65 123 !!";
const str2 = "123and 456 and 78-1";
const str3 = " Hello World    !!";

console.log(getFirstCharacters(str1));
console.log(getFirstCharacters(str2));
console.log(getFirstCharacters(str3));

Output:

[ 'H', 'W', '1', '!' ]

[ '1', '4', 'a', '7' ]

[ 'H', 'W', '!' ]

Upvotes: 1

Wiktor Stribiżew
Wiktor Stribiżew

Reputation: 626747

Getting first letter of any Unicode word in JavaScript is now easy with the ECMAScript 2018 standard:

/(?<!\p{L}\p{M}*)\p{L}/gu

This regex finds any Unicode letter (see the last \p{L}) that is not preceded with any other letter that can optionally have diacritic symbols (see the (?<!\p{L}\p{M}*) negative lookbehind where \p{M}* matches 0 or more diacritic chars). Note that u flag is compulsory here for the Unicode property classes (like \p{L}) to work correctly.

To emulate a fully Unicode-aware \b, you'd need to add a digit matching pattern and connector punctuation:

/(?<!\p{L}\p{M}*|[\p{N}\p{Pc}])\p{L}/gu

It works in Chrome, Firefox (since June 30, 2020), Node.js, and the majority of other environments (see the compatibility matrix here), for any natural language including Arabic.

Quick test:

const regex = /(?<!\p{L}\p{M}*)\p{L}/gu;
const string = "Żerard Łyżwiński";
// Extracting
console.log(string.match(regex));                        // => [ "Ż", "Ł" ]
// Extracting and concatenating into string
console.log(string.match(regex).join(""))                // => ŻŁ
// Removing
console.log(string.replace(regex, ""))                   // => erard yżwiński
// Enclosing (wrapping) with a tag
console.log(string.replace(regex, "<span>$&</span>"))    // => <span>Ż</span>erard <span>Ł</span>yżwiński

console.log("_Łukasz 1Żukowski".match(/(?<!\p{L}\p{M}*|[\p{N}\p{Pc}])\p{L}/gu)); // => null

Upvotes: 3

James
James

Reputation: 25513

If you came here looking for how to do this that supports non-BMP characters that use surrogate pairs:

initials = str.split(' ')
              .map(s => String.fromCodePoint(s.codePointAt(0) || '').toUpperCase())
              .join('');

Works in all modern browsers with no polyfills (not IE though)

Upvotes: 2

user3818229
user3818229

Reputation: 1617

ES6 reduce way:

const initials = inputStr.split(' ').reduce((result, currentWord) => 
    result + currentWord.charAt(0).toUpperCase(), '');
alert(initials);

Upvotes: 1

ihake
ihake

Reputation: 1831

This is similar to others, but (IMHO) a tad easier to read:

const getAcronym = title =>
  title.split(' ')
    .map(word => word[0])
    .join('');

Upvotes: 0

BotNet
BotNet

Reputation: 2809

I think what you're looking for is the acronym of a supplied string.

var str = "Java Script Object Notation";
var matches = str.match(/\b(\w)/g); // ['J','S','O','N']
var acronym = matches.join(''); // JSON

console.log(acronym)

Note: this will fail for hyphenated/apostrophe'd words Help-me I'm Dieing will be HmImD. If that's not what you want, the split on space, grab first letter approach might be what you want.

Here's a quick example of that:

let str = "Java Script Object Notation";
let acronym = str.split(/\s/).reduce((response,word)=> response+=word.slice(0,1),'')

console.log(acronym);

Upvotes: 213

Fatma Nabilla
Fatma Nabilla

Reputation: 1349

Alternative 1:

you can also use this regex to return an array of the first letter of every word

/(?<=(\s|^))[a-z]/gi

(?<=(\s|^)) is called positive lookbehind which make sure the element in our search pattern is preceded by (\s|^).

so, for your case:

// in case the input is lowercase & there's a word with apostrophe

const toAbbr = (str) => {
  return str.match(/(?<=(\s|^))[a-z]/gi)
            .join('')
            .toUpperCase();
};

toAbbr("java script object notation"); //result JSON

(by the way, there are also negative lookbehind, positive lookahead, negative lookahead, if you want to learn more)

Alternative 2:

match all the words and use replace() method to replace them with the first letter of each word and ignore the space (the method will not mutate your original string)

// in case the input is lowercase & there's a word with apostrophe    

const toAbbr = (str) => {
  return str.replace(/(\S+)(\s*)/gi, (match, p1, p2) => p1[0].toUpperCase());
};

toAbbr("java script object notation"); //result JSON

// word = not space = \S+ = p1 (p1 is the first pattern)
// space = \s* = p2 (p2 is the second pattern)

Upvotes: 2

Darryl Hebbes
Darryl Hebbes

Reputation: 1028

To add to the great examples, you could do it like this in ES6

const x = "Java Script Object Notation".split(' ').map(x => x[0]).join('');
console.log(x);  // JSON

and this works too but please ignore it, I went a bit nuts here :-)

const [j,s,o,n] = "Java Script Object Notation".split(' ').map(x => x[0]);
console.log(`${j}${s}${o}${n}`);

Upvotes: 5

tomersss2
tomersss2

Reputation: 155

@BotNet flaw: i think i solved it after excruciating 3 days of regular expressions tutorials:

==> I'm a an animal

(used to catch m of I'm) because of the word boundary, it seems to work for me that way.

/(\s|^)([a-z])/gi

Upvotes: 3

Vadim Gremyachev
Vadim Gremyachev

Reputation: 59328

Yet another option using reduce function:

var value = "Java Script Object Notation";

var result = value.split(' ').reduce(function(previous, current){
    return {v : previous.v + current[0]};
},{v:""});


$("#output").text(result.v);
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<pre id="output"/>

Upvotes: 0

Ben Sarah Golightly
Ben Sarah Golightly

Reputation: 472

Using map (from functional programming)

'use strict';

function acronym(words)
{
    if (!words) { return ''; }

    var first_letter = function(x){ if (x) { return x[0]; } else { return ''; }};

    return words.split(' ').map(first_letter).join('');
}

Upvotes: 2

SondreB
SondreB

Reputation: 808

The regular expression versions for JavaScript is not compatible with Unicode on older than ECMAScript 6, so for those who want to support characters such as "å" will need to rely on non-regex versions of scripts.

Event when on version 6, you need to indicate Unicode with \u.

More details: https://mathiasbynens.be/notes/es6-unicode-regex

Upvotes: 0

Almis
Almis

Reputation: 3809

Easiest way without regex 

var abbr = "Java Script Object Notation".split(' ').map(function(item){return item[0]}).join('');

Upvotes: 28

JesseBuesking
JesseBuesking

Reputation: 6586

This should do it.

var s = "Java Script Object Notation",
    a = s.split(' '),
    l = a.length,
    i = 0,
    n = "";

for (; i < l; ++i)
{
    n += a[i].charAt(0);
}

console.log(n);

Upvotes: 0

hugomg
hugomg

Reputation: 69934

I think you can do this with

'Aa Bb'.match(/\b\w/g).join('')

Explanation: Obtain all /g the alphanumeric characters \w that occur after a non-alphanumeric character (i.e: after a word boundary \b), put them on an array with .match() and join everything in a single string .join('')

Depending on what you want to do you can also consider simply selecting all the uppercase characters:

'JavaScript Object Notation'.match(/[A-Z]/g).join('')

Upvotes: 32

ipr101
ipr101

Reputation: 24236

Try -

var text = '';
var arr = "Java Script Object Notation".split(' ');
for(i=0;i<arr.length;i++) {
    text += arr[i].substr(0,1)
}    
alert(text);

Demo - http://jsfiddle.net/r2maQ/

Upvotes: 1

Madara&#39;s Ghost
Madara&#39;s Ghost

Reputation: 174957

How about this:

var str = "", abbr = "";
str = "Java Script Object Notation";
str = str.split(' ');
for (i = 0; i < str.length; i++) {
    abbr += str[i].substr(0,1);
}
alert(abbr);

Working Example.

Upvotes: 1

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