How do I make the first character of a string uppercase if it's a letter, but not change the case of any of the other letters?
For example:
"this is a test"
→"This is a test"
"the Eiffel Tower"
→"The Eiffel Tower"
"/index.html"
→"/index.html"
How do I make the first character of a string uppercase if it's a letter, but not change the case of any of the other letters?
For example:
"this is a test"
→ "This is a test"
"the Eiffel Tower"
→ "The Eiffel Tower"
"/index.html"
→ "/index.html"
function capitalizeFirstLetter(val) {
return String(val).charAt(0).toUpperCase() + String(val).slice(1);
}
Some other answers modify String.prototype
(this answer used to as well), but I would advise against this now due to maintainability (hard to find out where the function is being added to the prototype
and could cause conflicts if other code uses the same name/a browser adds a native function with that same name in future).
string
: const capitalize = <T extends string>(s: T) => (s[0].toUpperCase() + s.slice(1)) as Capitalize<typeof s>;
Commented
Mar 27, 2023 at 17:56
charAt
splits at UTF16 code units. There are characters with case-folding definitions in the SMP that are encoded with two UTF16 code units. While simple, this shouldn't be used.
Commented
Sep 28, 2023 at 7:34
"flat"
is returned as "FLat"
.
Commented
Sep 28, 2023 at 7:42
Edited to add this DISCLAIMER: please read the comments to understand the risks of editing JS basic types.
Here's a more object-oriented approach:
Object.defineProperty(String.prototype, 'capitalize', {
value: function() {
return this.charAt(0).toUpperCase() + this.slice(1);
},
enumerable: false
});
You'd call the function, like this:
"hello, world!".capitalize();
With the expected output being:
"Hello, world!"
Using just CSS and its text-transform
property:
p::first-letter {
text-transform: capitalize;
}
::first-letter
works ONLY on elements with a display
value of block
, inline-block
, table-cell
, list-item
or table-caption
. In all other cases, ::first-letter
has no effect.
Commented
Dec 8, 2021 at 13:11
flex
and grid
....
title
property for example. therefore you're not answering at all the question !
Here is a shortened version of the popular answer that gets the first letter by treating the string as an array:
function capitalize(s)
{
return String(s[0]).toUpperCase() + String(s).slice(1);
}
According to the comments below this doesn't work in IE 7 or below.
To avoid undefined
for empty strings (see @njzk2's comment below), you can check for an empty string:
function capitalize(s)
{
return s && String(s[0]).toUpperCase() + String(s).slice(1);
}
const capitalize = s => s && String(s[0]).toUpperCase() + String(s).slice(1)
// to always return type string event when s may be falsy other than empty-string
const capitalize = s => (s && String(s[0]).toUpperCase() + String(s).slice(1)) || ""
s ? s[0].toUpperCase() + s.slice(1) : ""
more readable
elem.name[0].toUpperCase() + elem.name.slice(1)
Here are the fastest methods based on this jsperf test (ordered from fastest to slowest).
As you can see, the first two methods are essentially comparable in terms of performance, whereas altering the String.prototype
is by far the slowest in terms of performance.
// 10,889,187 operations/sec
function capitalizeFirstLetter(string) {
return string[0].toUpperCase() + string.slice(1);
}
// 10,875,535 operations/sec
function capitalizeFirstLetter(string) {
return string.charAt(0).toUpperCase() + string.slice(1);
}
// 4,632,536 operations/sec
function capitalizeFirstLetter(string) {
return string.replace(/^./, string[0].toUpperCase());
}
// 1,977,828 operations/sec
String.prototype.capitalizeFirstLetter = function() {
return this.charAt(0).toUpperCase() + this.slice(1);
}
I didn’t see any mention in the existing answers of issues related to astral plane code points or internationalization. “Uppercase” doesn’t mean the same thing in every language using a given script.
Initially I didn’t see any answers addressing issues related to astral plane code points. There is one, but it’s a bit buried (like this one will be, I guess!)
Most of the proposed functions look like this:
function capitalizeFirstLetter(str) {
return str[0].toUpperCase() + str.slice(1);
}
However, some cased characters fall outside the BMP (basic multilingual plane, code points U+0 to U+FFFF). For example take this Deseret text:
capitalizeFirstLetter("𐐶𐐲𐑌𐐼𐐲𐑉"); // "𐐶𐐲𐑌𐐼𐐲𐑉"
The first character here fails to capitalize because the array-indexed properties of strings don’t access “characters” or code points*. They access UTF-16 code units. This is true also when slicing — the index values point at code units.
It happens to be that UTF-16 code units are 1:1 with USV (Unicode scalar value) code points within two ranges, U+0 to U+D7FF and U+E000 to U+FFFF inclusive. Most cased characters fall into those two ranges, but not all of them.
From ES2015 on, dealing with this became a bit easier. String.prototype[@@iterator]
yields strings corresponding to code points**. So for example, we can do this:
function capitalizeFirstLetter([ first='', ...rest ]) {
return [ first.toUpperCase(), ...rest ].join('');
}
capitalizeFirstLetter("𐐶𐐲𐑌𐐼𐐲𐑉") // "𐐎𐐲𐑌𐐼𐐲𐑉"
For longer strings, this is probably not terribly efficient*** — we don’t really need to iterate the remainder. We could use String.prototype.codePointAt
to get at that first (possible) letter, but we’d still need to determine where the slice should begin. One way to avoid iterating the remainder would be to test whether the first codepoint is outside the BMP; if it isn’t, the slice begins at 1, and if it is, the slice begins at 2.
function capitalizeFirstLetter(str) {
if (!str) return '';
const firstCodePoint = str.codePointAt(0);
const index = firstCodePoint > 0xFFFF ? 2 : 1;
return String.fromCodePoint(firstCodePoint).toUpperCase() + str.slice(index);
}
capitalizeFirstLetter("𐐶𐐲𐑌𐐼𐐲𐑉") // "𐐎𐐲𐑌𐐼𐐲𐑉"
You could use bitwise math instead of > 0xFFFF
there, but it’s probably easier to understand this way and either would achieve the same thing.
We can also make this work in ES5 and below by taking that logic a bit further if necessary. There are no intrinsic methods in ES5 for working with codepoints, so we have to manually test whether the first code unit is a surrogate****:
function capitalizeFirstLetter(str) {
if (!str) return '';
var firstCodeUnit = str[0];
if (firstCodeUnit < '\uD800' || firstCodeUnit > '\uDFFF') {
return str[0].toUpperCase() + str.slice(1);
}
return str.slice(0, 2).toUpperCase() + str.slice(2);
}
capitalizeFirstLetter("𐐶𐐲𐑌𐐼𐐲𐑉") // "𐐎𐐲𐑌𐐼𐐲𐑉"
At the start I also mentioned internationalization considerations. Some of these are very difficult to account for because they require knowledge not only of what language is being used, but also may require specific knowledge of the words in the language. For example, the Irish digraph "mb" capitalizes as "mB" at the start of a word. Another example, the German eszett, never begins a word (afaik), but still helps illustrate the problem. The lowercase eszett (“ß”) capitalizes to “SS,” but “SS” could lowercase to either “ß” or “ss” — you require out-of-band knowledge of the German language to know which is correct!
The most famous example of these kinds of issues, probably, is Turkish. In Turkish Latin, the capital form of i is İ, while the lowercase form of I is ı — they’re two different letters. Fortunately we do have a way to account for this:
function capitalizeFirstLetter([ first='', ...rest ], locale) {
return [ first.toLocaleUpperCase(locale), ...rest ].join('');
}
capitalizeFirstLetter("italy", "en") // "Italy"
capitalizeFirstLetter("italya", "tr") // "İtalya"
In a browser, the user’s most-preferred language tag is indicated by navigator.language
, a list in order of preference is found at navigator.languages
, and a given DOM element’s language can be obtained (usually) with Object(element.closest('[lang]')).lang || YOUR_DEFAULT_HERE
in multilanguage documents.
In agents which support Unicode property character classes in RegExp, which were introduced in ES2018, we can clean stuff up further by directly expressing what characters we’re interested in:
function capitalizeFirstLetter(str, locale=navigator.language) {
return str.replace(/^\p{CWU}/u, char => char.toLocaleUpperCase(locale));
}
This could be tweaked a bit to also handle capitalizing multiple words in a string with fairly good accuracy for at least some languages, though outlying cases will be hard to avoid completely if doing so no matter what the primary language is.
The \p{CWU}
or Changes_When_Uppercased character property matches all code points which change when uppercased in the generic case where specific locale data is absent. There are other interesting case-related Unicode character properties that you may wish to play around with. It’s a cool zone to explore but we’d go on all day if we enumerated em all here. Here’s something to get your curiosity going if you’re unfamiliar, though: \p{Lower}
is a larger group than \p{LowercaseLetter}
(aka \p{Ll}
) — conveniently illustrated by the default character set comparison in this tool provided by Unicode. (NB: not everything you can reference there is also available in ES regular expressions, but most of the stuff you’re likely to want is).
If digraphs with unique locale/language/orthography capitalization rules happen to have a single-codepoint “composed” representation in Unicode, these might be used to make one’s capitalization expectations explicit even in the absence of locale data. For example, we could prefer the composed i-j digraph, ij / U+133, associated with Dutch, to ensure a case-mapping to uppercase IJ / U+132:
capitalizeFirstLetter('ijsselmeer'); // "IJsselmeer"
On the other hand, precomposed digraphs and similar are sometimes deprecated (like that one, it seems!) and may be undesirable in interchanged text regardless due to the potential copypaste nuisance if that’s not the normal way folks type the sequence in practice. Unfortunately, in the absence of the precomposition “hint,” an explicit locale won’t help here (at least as far as I know). If we spell ijsselmeer
with an ordinary i
+ j
, capitalizeFirstLetter
will produce the wrong result even if we explicitly indicate nl
as the locale:
capitalizeFirstLetter('ijsselmeer', 'nl'); // "Ijsselmeer" :(
(I’m not entirely sure whether there are some such cases where the behavior comes down to ICU data availability — perhaps someone else could say.)
If the point of the transformation is to display textual content in a web browser, though, you have an entirely different option available that will likely be your best bet: leveraging features of the web platform’s other core languages, HTML and CSS. Armed with HTML’s lang=...
and CSS’s text-transform:...
, you’ve got a (pseudo-)declarative solution that leaves extra room for the user agent to be “smart.” A JS API needs to have predictable outcomes across all browsers (generally) and isn’t free to experiment with heuristics. The user-agent itself is obligated only to its user, though, and heuristic solutions are fair game when the output is for a human being. If we tell it “this text is Dutch, but please display it capitalized,” the particular outcome might now vary between browsers, but it’s likely going to be the best each of them could do. Let’s see:
<!DOCTYPE html>
<dl>
<dt>Untransformed
<dd>ijsselmeer
<dt>Capitalized with CSS and <code>lang=en</code>
<dd lang="en" style="text-transform: capitalize">ijsselmeer
<dt>Capitalized with CSS and <code>lang=nl</code>
<dd lang="nl" style="text-transform: capitalize">ijsselmeer
In Chromium at the time of writing, both the English and Dutch lines come out as Ijsselmeer
— so it does no better than JS. But try it in current Firefox! The element that we told the browser contains Dutch will be correctly rendered as IJsselmeer
there.
This solution is purpose-specific (it’s not gonna help you in Node, anyway) but it was silly of me not to draw attention to it previously given some folks might not realize they’re googling the wrong question. Thanks @paul23 for clarifying more about the nature of the IJ digraph in practice and prompting further investigation!
As of January 2021, all major engines have implemented the Unicode property character class feature, but depending on your target support range you may not be able to use it safely yet. The last browser to introduce support was Firefox (78; June 30, 2020). You can check for support of this feature with the Kangax compat table. Babel can be used to compile RegExp literals with property references to equivalent patterns without them, but be aware that the resulting code can sometimes be enormous. You probably would not want to do this unless you’re certain the tradeoff is justified for your use case.
In all likelihood, people asking this question will not be concerned with Deseret capitalization or internationalization. But it’s good to be aware of these issues because there’s a good chance you’ll encounter them eventually even if they aren’t concerns presently. They’re not “edge” cases, or rather, they’re not by-definition edge cases — there’s a whole country where most people speak Turkish, anyway, and conflating code units with codepoints is a fairly common source of bugs (especially with regard to emoji). Both strings and language are pretty complicated!
* The code units of UTF-16 / UCS2 are also Unicode code points in the sense that e.g. U+D800 is technically a code point, but that’s not what it “means” here ... sort of ... though it gets pretty fuzzy. What the surrogates definitely are not, though, is USVs (Unicode scalar values).
** Though if a surrogate code unit is “orphaned” — i.e., not part of a logical pair — you could still get surrogates here, too.
*** maybe. I haven’t tested it. Unless you have determined capitalization is a meaningful bottleneck, I probably wouldn’t sweat it — choose whatever you believe is most clear and readable.
**** such a function might wish to test both the first and second code units instead of just the first, since it’s possible that the first unit is an orphaned surrogate. For example the input "\uD800x" would capitalize the X as-is, which may or may not be expected.
toUpperCase
didn't really do much for some languages... but didn't quite care enough to find out. Glad I finally did, this was a very interesting read!
Commented
Jul 19, 2021 at 22:09
capitalizeFirstLetter('ijssel', 'nl-NL')
- That's a correct localization string right?
granularity: "word"
.
Commented
Jul 23 at 19:19
For another case I need it to capitalize the first letter and lowercase the rest. The following cases made me change this function:
//es5
function capitalize(string) {
return string.charAt(0).toUpperCase() + string.slice(1).toLowerCase();
}
capitalize("alfredo") // => "Alfredo"
capitalize("Alejandro")// => "Alejandro
capitalize("ALBERTO") // => "Alberto"
capitalize("ArMaNdO") // => "Armando"
// es6 using destructuring
const capitalize = ([first,...rest]) => first.toUpperCase() + rest.join('').toLowerCase();
If you're already (or considering) using Lodash, the solution is easy:
_.upperFirst('fred');
// => 'Fred'
_.upperFirst('FRED');
// => 'FRED'
_.capitalize('fred') //=> 'Fred'
See their documentation: https://lodash.com/docs#capitalize
_.camelCase('Foo Bar'); //=> 'fooBar'
https://lodash.com/docs/4.15.0#camelCase
_.lowerFirst('Fred');
// => 'fred'
_.lowerFirst('FRED');
// => 'fRED'
_.snakeCase('Foo Bar');
// => 'foo_bar'
Vanilla JavaScript for first upper case:
function upperCaseFirst(str){
return str.charAt(0).toUpperCase() + str.substring(1);
}
_.startCase('fred') //=> 'Fred'
_.startCase('fred doe') //=> 'Fred Doe'
. note it removes hyphen eg. _.startCase('fred-doe') //=> 'Fred Doe'
Commented
Jul 28 at 11:21
This is the 2018 ECMAScript 6+ Solution:
const str = 'the Eiffel Tower';
const newStr = `${str[0].toUpperCase()}${str.slice(1)}`;
console.log('Original String:', str); // the Eiffel Tower
console.log('New String:', newStr); // The Eiffel Tower
There is a very simple way to implement it by replace. For ECMAScript 6:
'foo'.replace(/^./, str => str.toUpperCase())
Result:
'Foo'
/^[a-z]/i
will be better than using .
as the prior one will not try to replace any character other than alphabets
Commented
Jul 6, 2019 at 5:56
string
variable (that most other answers assume there is). For example: const date = new Date("2024-08-12").toLocaleDateString("fr-FR", { weekday: "long", year: "numeric", month: "long", day: "numeric" }).replace(/^./, str => str.toUpperCase());
. Using the string concatenation solution would require putting the locale date string in a variable first (or worse, repeating the full date method).
Commented
Aug 12 at 10:52
If the transformation is needed only for displaying on a web page:
p::first-letter {
text-transform: uppercase;
}
::first-letter
", it applies to the first character, i.e. in case of string %a
, this selector would apply to %
and as such a
would not be capitalized.:first-letter
).const capitalizeFirstChar = str => str.charAt(0).toUpperCase() + str.substring(1);
string.charAt(0)
and string[0]
. Note however, that string[0]
would be undefined
for an empty string, so the function would have to be rewritten to use "string && string[0]
", which is way too verbose, compared to the alternative.string.substring(1)
is faster than string.slice(1)
.substring()
and slice()
The difference is rather minuscule nowadays (run the test yourself):
substring()
,slice()
.Capitalize the first letter of all words in a string:
function ucFirstAllWords( str )
{
var pieces = str.split(" ");
for ( var i = 0; i < pieces.length; i++ )
{
var j = pieces[i].charAt(0).toUpperCase();
pieces[i] = j + pieces[i].substr(1);
}
return pieces.join(" ");
}
s => s.split(' ').map(x => x[0].toUpperCase() + x.slice(1)).join(' ')
Commented
Jul 28, 2017 at 18:10
It's always better to handle these kinds of stuff using CSS first, in general, if you can solve something using CSS, go for that first, then try JavaScript to solve your problems, so in this case try using :first-letter
in CSS and apply text-transform:capitalize;
So try creating a class for that, so you can use it globally, for example: .first-letter-uppercase
and add something like below in your CSS:
.first-letter-uppercase:first-letter {
text-transform:capitalize;
}
Also the alternative option is JavaScript, so the best gonna be something like this:
function capitalizeTxt(txt) {
return txt.charAt(0).toUpperCase() + txt.slice(1); //or if you want lowercase the rest txt.slice(1).toLowerCase();
}
and call it like:
capitalizeTxt('this is a test'); // return 'This is a test'
capitalizeTxt('the Eiffel Tower'); // return 'The Eiffel Tower'
capitalizeTxt('/index.html'); // return '/index.html'
capitalizeTxt('alireza'); // return 'Alireza'
capitalizeTxt('dezfoolian'); // return 'Dezfoolian'
If you want to reuse it over and over, it's better attach it to javascript native String, so something like below:
String.prototype.capitalizeTxt = String.prototype.capitalizeTxt || function() {
return this.charAt(0).toUpperCase() + this.slice(1);
}
and call it as below:
'this is a test'.capitalizeTxt(); // return 'This is a test'
'the Eiffel Tower'.capitalizeTxt(); // return 'The Eiffel Tower'
'/index.html'.capitalizeTxt(); // return '/index.html'
'alireza'.capitalizeTxt(); // return 'Alireza'
String.prototype.capitalize = function(allWords) {
return (allWords) ? // If all words
this.split(' ').map(word => word.capitalize()).join(' ') : // Break down the phrase to words and then recursive
// calls until capitalizing all words
this.charAt(0).toUpperCase() + this.slice(1); // If allWords is undefined, capitalize only the first word,
// meaning the first character of the whole string
}
And then:
"capitalize just the first word".capitalize(); ==> "Capitalize just the first word"
"capitalize all words".capitalize(true); ==> "Capitalize All Words"
const capitalize = (string = '') => [...string].map( // Convert to array with each item is a char of
// string by using spread operator (...)
(char, index) => index ? char : char.toUpperCase() // Index true means not equal 0, so (!index) is
// the first character which is capitalized by
// the `toUpperCase()` method
).join('') // Return back to string
then capitalize("hello") // Hello
const capitalize = ([first,...rest]) => first.toUpperCase() + rest.join('').toLowerCase();
.
Commented
Jun 22, 2019 at 5:50
SHORTEST 3 solutions, 1 and 2 handle cases when s
string is ""
, null
and undefined
:
s&&s[0].toUpperCase()+s.slice(1) // 32 char
s&&s.replace(/./,s[0].toUpperCase()) // 36 char - using regexp
'foo'.replace(/./,x=>x.toUpperCase()) // 31 char - direct on string, ES6
let s='foo bar';
console.log( s&&s[0].toUpperCase()+s.slice(1) );
console.log( s&&s.replace(/./,s[0].toUpperCase()) );
console.log( 'foo bar'.replace(/./,x=>x.toUpperCase()) );
We could get the first character with one of my favorite RegExp
, looks like a cute smiley: /^./
String.prototype.capitalize = function () {
return this.replace(/^./, function (match) {
return match.toUpperCase();
});
};
And for all coffee-junkies:
String::capitalize = ->
@replace /^./, (match) ->
match.toUpperCase()
...and for all guys who think that there's a better way of doing this, without extending native prototypes:
var capitalize = function (input) {
return input.replace(/^./, function (match) {
return match.toUpperCase();
});
};
'Answer'.replace(/^./, v => v.toLowerCase())
Here is a function called ucfirst()
(short for "upper case first letter"):
function ucfirst(str) {
var firstLetter = str.substr(0, 1);
return firstLetter.toUpperCase() + str.substr(1);
}
You can capitalise a string by calling ucfirst("some string")
-- for example,
ucfirst("this is a test") --> "This is a test"
It works by splitting the string into two pieces. On the first line it pulls out firstLetter
and then on the second line it capitalises firstLetter
by calling firstLetter.toUpperCase()
and joins it with the rest of the string, which is found by calling str.substr(1)
.
You might think this would fail for an empty string, and indeed in a language like C you would have to cater for this. However in JavaScript, when you take a substring of an empty string, you just get an empty string back.
substr()
is deprecated? It's not, even now, three years later, let alone back in 2009 when you made this comment.
Commented
Nov 7, 2012 at 6:12
substr()
may not be marked as deprecated by any popular ECMAScript implementation (I doubt it's not going to disappear anytime soon), but it's not part of the ECMAScript spec. The 3rd edition of the spec mentions it in the non-normative annex in order to "suggests uniform semantics for such properties without making the properties or their semantics part of this standard".
Commented
Nov 21, 2012 at 22:05
substring
, substr
and slice
) is too many, IMO. I always use slice
because it supports negative indexes, it doesn't have the confusing arg-swapping behavior and its API is similar to slice
in other languages.
Commented
Nov 21, 2012 at 22:12
If you're ok with capitalizing the first letter of every word, and your usecase is in HTML, you can use the following CSS:
<style type="text/css">
p.capitalize {text-transform:capitalize;}
</style>
<p class="capitalize">This is some text.</p>
This is from CSS text-transform Property (at W3Schools).
Use:
var str = "ruby java";
console.log(str.charAt(0).toUpperCase() + str.substring(1));
It will output "Ruby java"
to the console.
If you use Underscore.js or Lodash, the underscore.string library provides string extensions, including capitalize:
_.capitalize(string) Converts first letter of the string to uppercase.
Example:
_.capitalize("foo bar") == "Foo bar"
humanize
. It converts an underscored, camelized, or dasherized string into a humanized one. Also removes beginning and ending whitespace, and removes the postfix '_id'.
Commented
May 7, 2015 at 14:11
If you are wanting to reformat all-caps text, you might want to modify the other examples as such:
function capitalize (text) {
return text.charAt(0).toUpperCase() + text.slice(1).toLowerCase();
}
This will ensure that the following text is changed:
TEST => Test
This Is A TeST => This is a test
function capitalize(s) {
// returns the first letter capitalized + the string from index 1 and out aka. the rest of the string
return s[0].toUpperCase() + s.substr(1);
}
// examples
capitalize('this is a test');
=> 'This is a test'
capitalize('the Eiffel Tower');
=> 'The Eiffel Tower'
capitalize('/index.html');
=> '/index.html'
substr
/substring
is a bit more semantic as opposed to slice
, but that's just a matter of preference. I did however include examples with the strings provided in the question, which is a nice touch not present in the '09 example. I honestly think it boils down to 15 year old me wanting karma on StackOverflow ;)
yourString.replace(/\w/, c => c.toUpperCase())
I found this arrow function easiest. Replace matches the first letter character (\w
) of your string and converts it to uppercase. Nothing fancier is necessary.
/./
for two reason: /\w/
will skip all the previous not letter characters (so @@abc will become @@Abc), and then it doesn't work with not-latin characters
Commented
Apr 29, 2019 at 18:01
\w Matches any alphanumeric character from the basic Latin alphabet, including the underscore.
so replacing a word like _boss
will yield _boss
(from developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/…)
Commented
May 5, 2022 at 17:25
1boss
. If matching an underscore is not the desired behaviour, use [A-Za-z-0-9]
or [^\W_]
.
String.prototype.capitalize = function(){
return this.replace(/(^|\s)([a-z])/g,
function(m, p1, p2) {
return p1 + p2.toUpperCase();
});
};
Usage:
capitalizedString = someString.capitalize();
This is a text string => This Is A Text String
return.this.toLocaleLowerCase().replace(
...
Commented
Jan 14, 2013 at 21:55
String.prototype.capitalize = function(){ return this.replace( /(^|\s)[a-z]/g , function(m){ return m.toUpperCase(); }); };
I refactor your code a bit, you need only a first match.
57 81 different answers for this question, some off-topic, and yet none of them raise the important issue that none of the solutions listed will work with Asian characters, emoji's, and other high Unicode-point-value characters in many browsers. Here is a solution that will:
const consistantCapitalizeFirstLetter = "\uD852\uDF62".length === 1 ?
function(S) {
"use-strict"; // Hooray! The browser uses UTF-32!
return S.charAt(0).toUpperCase() + S.substring(1);
} : function(S) {
"use-strict";
// The browser is using UCS16 to store UTF-16
var code = S.charCodeAt(0)|0;
return (
code >= 0xD800 && code <= 0xDBFF ? // Detect surrogate pair
S.slice(0,2).toUpperCase() + S.substring(2) :
S.charAt(0).toUpperCase() + S.substring(1)
);
};
const prettyCapitalizeFirstLetter = "\uD852\uDF62".length === 1 ?
function(S) {
"use-strict"; // Hooray! The browser uses UTF-32!
return S.charAt(0).toLocaleUpperCase() + S.substring(1);
} : function(S) {
"use-strict";
// The browser is using UCS16 to store UTF-16
var code = S.charCodeAt(0)|0;
return (
code >= 0xD800 && code <= 0xDBFF ? // Detect surrogate pair
S.slice(0,2).toLocaleUpperCase() + S.substring(2) :
S.charAt(0).toLocaleUpperCase() + S.substring(1)
);
};
Do note that the above solution tries to account for UTF-32. However, the specification officially states that browsers are required to do everything in UTF-16 mapped into UCS2. Nevertheless, if we all come together, do our part, and start preparing for UTF32, then there is a chance that the TC39 may allow browsers to start using UTF-32 (like how Python uses 24-bits for each character of the string). This must seem silly to an English speaker: no one who uses only latin-1 has ever had to deal with Mojibake because Latin-I is supported by all character encodings. But, users in other countries (such as China, Japan, Indonesia, etc.) are not so fortunate. They constantly struggle with encoding problems not just from the webpage, but also from the JavaScript: many Chinese/Japanese characters are treated as two letters by JavaScript and thus may be broken apart in the middle, resulting in � and � (two question-marks that make no sense to the end user). If we could start getting ready for UTF-32, then the TC39 might just allow browsers do what Python did many years ago which had made Python very popular for working with high Unicode characters: using UTF-32.
consistantCapitalizeFirstLetter
works correctly in Internet Explorer 3+ (when the const
is changed to var
). prettyCapitalizeFirstLetter
requires Internet Explorer 5.5+ (see the top of page 250 of this document). However, these fact are more of just jokes because it is very likely that the rest of the code on your webpage will not even work in Internet Explorer 8 - because of all the DOM and JScript bugs and lack of features in these older browsers. Further, no one uses Internet Explorer 3 or Internet Explorer 5.5 any more.
String.fromCodePoint(65536).length === 1
will be true. That ES strings expose their UTF16ishness isn’t implementation-specific behavior — it’s a well-defined part of the spec, and it can’t be fixed due to backwards compat.
Commented
Dec 26, 2018 at 10:48
S
or string
?
var str = "test string";
str = str.substring(0,1).toUpperCase() + str.substring(1);
Check out this solution:
var stringVal = 'master';
stringVal.replace(/^./, stringVal[0].toUpperCase()); // Returns Master
stringVal.replace(/^./, stringVal[0].toUpperCase());
Commented
Oct 15, 2015 at 19:30
stringVal[0]
would be undefined
for empty stringVal
, and as such attempt to access property .toUpperCase()
would throw an error.
with arrow function
let fLCapital = s => s.replace(/./, c => c.toUpperCase())
fLCapital('this is a test') // "This is a test"
with arrow function, another solution
let fLCapital = s => s = s.charAt(0).toUpperCase() + s.slice(1);
fLCapital('this is a test') // "This is a test"
with array and map()
let namesCapital = names => names.map(name => name.replace(/./, c => c.toUpperCase()))
namesCapital(['james', 'robert', 'mary']) // ["James", "Robert", "Mary"]
There are already so many good answers, but you can also use a simple CSS transform:
text-transform: capitalize;
div.text-capitalize {
text-transform: capitalize;
}
<h2>text-transform: capitalize:</h2>
<div class="text-capitalize">Lorem ipsum dolor sit amet, consectetur adipiscing elit.</div>