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

Question

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

Answer 1

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}`);

Answer 2

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

Answer 3

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);

Answer 4

ES6 reduce way:

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

Answer 5

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('');
}

Answer 6

Easiest way without regex

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