Show all function: Try String.prototype & String in browser console.
fromCharCode
1
2
| console.log(String.fromCharCode(189, 43, 190, 61));
// expected output: "½+¾="
|
fromCodePoint
1
2
| console.log(String.fromCodePoint(9731, 9733, 9842, 0x2f804));
// expected output: "☃★♲你"
|
raw
1
2
3
4
5
6
| // Create a variable that uses a Windows
// path without escaping the backslashes:
const filePath = String.raw`C:\Development\profile\aboutme.html`;
console.log(`The file was uploaded from: ${filePath}`);
// expected output: "The file was uploaded from: C:\Development\profile\aboutme.html"
|
charAt
1
2
3
4
5
6
| const sentence = 'The quick brown fox jumps over the lazy dog.';
const index = 4;
console.log(`The character at index ${index} is ${sentence.charAt(index)}`);
// expected output: "The character at index 4 is q"
|
charCodeAt
1
2
3
4
5
6
7
8
9
10
| const sentence = 'The quick brown fox jumps over the lazy dog.';
const index = 4;
console.log(
`The character code ${sentence.charCodeAt(
index
)} is equal to ${sentence.charAt(index)}`
);
// expected output: "The character code 113 is equal to q"
|
codePointAt
1
2
3
4
| const icons = '☃★♲';
console.log(icons.codePointAt(1));
// expected output: "9733"
|
concat
1
2
3
4
5
6
7
8
| const str1 = 'Hello';
const str2 = 'World';
console.log(str1.concat(' ', str2));
// expected output: "Hello World"
console.log(str2.concat(', ', str1));
// expected output: "World, Hello"
|
startsWith
1
2
3
4
5
6
7
8
9
10
| const str1 = 'Saturday night plans';
console.log(str1.startsWith('Sat'));
// expected output: true
console.log(str1.startsWith('Sat', 3));
// expected output: false
console.log(str1.startsWith('ur', 3));
// true
|
endsWith
1
2
3
4
5
6
7
8
9
| const str1 = 'Cats are the best!'; // len == 18
console.log(str1.endsWith('best', 17));
// expected output: true
const str2 = 'Is this a question';
console.log(str2.endsWith('?'));
// expected output: false
|
includes
1
2
3
4
5
6
7
8
9
10
| const sentence = 'The quick brown fox jumps over the lazy dog.';
const word = 'fox';
console.log(
`The word "${word}" ${
sentence.includes(word) ? 'is' : 'is not'
} in the sentence`
);
// expected output: "The word "fox" is in the sentence"
|
indexOf
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
| const paragraph =
'The quick brown fox jumps over the lazy dog. If the dog barked, was it really lazy?';
const searchTerm = 'dog';
const indexOfFirst = paragraph.indexOf(searchTerm);
console.log(
`The index of the first "${searchTerm}" from the beginning is ${indexOfFirst}`
);
// expected output: "The index of the first "dog" from the beginning is 40"
console.log(
`The index of the 2nd "${searchTerm}" is ${paragraph.indexOf(
searchTerm,
indexOfFirst + 1
)}`
);
// expected output: "The index of the 2nd "dog" is 52"
|
lastIndexOf
1
2
3
4
5
6
7
8
9
10
11
| const paragraph =
'The quick brown fox jumps over the lazy dog. If the dog barked, was it really lazy?';
const searchTerm = 'dog';
console.log(
`The index of the first "${searchTerm}" from the end is ${paragraph.lastIndexOf(
searchTerm
)}`
);
// expected output: "The index of the first "dog" from the end is 52"
|
localeCompare
1
2
3
4
5
6
7
| const a = 'réservé'; // with accents, lowercase
const b = 'RESERVE'; // no accents, uppercase
console.log(a.localeCompare(b));
// expected output: 1
console.log(a.localeCompare(b, 'en', { sensitivity: 'base' }));
// expected output: 0
|
match
1
2
3
4
5
6
| const paragraph = 'The quick brown fox jumps over the lazy dog. It barked.';
const regex = /[A-Z]/g;
const found = paragraph.match(regex);
console.log(found);
// expected output: Array ["T", "I"]
|
matchAll
The matchAll() method returns an iterator of all results matching a string against a regular expression, including capturing groups.
1
2
3
4
5
6
7
| const regexp = /t(e)(st(\d?))/g;
const str = 'test1test2';
const array = [...str.matchAll(regexp)];
console.log(array);
// [["test1", "e", "st1", "1"] ["test2", "e", "st2", "2"]]
|
normalize
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
| const name1 = '\u0041\u006d\u00e9\u006c\u0069\u0065';
const name2 = '\u0041\u006d\u0065\u0301\u006c\u0069\u0065';
console.log(`${name1}, ${name2}`);
// expected output: "Amélie, Amélie"
console.log(name1 === name2);
// expected output: false
console.log(name1.length === name2.length);
// expected output: false
const name1NFC = name1.normalize('NFC');
const name2NFC = name2.normalize('NFC');
console.log(`${name1NFC}, ${name2NFC}`);
// expected output: "Amélie, Amélie"
console.log(name1NFC === name2NFC);
// expected output: true
console.log(name1NFC.length === name2NFC.length);
// expected output: true
|
padEnd
1
2
3
4
5
6
7
8
9
| const str1 = 'Breaded Mushrooms';
console.log(str1.padEnd(25, '.'));
// expected output: "Breaded Mushrooms........" // new str len == 25
const str2 = '200';
console.log(str2.padEnd(5));
// expected output: "200 "
|
padStart
1
2
3
4
5
6
7
8
9
10
11
| const str1 = '5';
console.log(str1.padStart(2, '0'));
// expected output: "05"
const fullNumber = '2034399002125581';
const last4Digits = fullNumber.slice(-4);
const maskedNumber = last4Digits.padStart(fullNumber.length, '*');
console.log(maskedNumber);
// expected output: "************5581"
|
repeat
1
2
3
4
| const chorus = "Because I'm happy. ";
console.log(`Chorus lyrics for "Happy": ${chorus.repeat(3)}`);
//"Chorus lyrics for "Happy": Because I'm happy. Because I'm happy. Because I'm happy. "
|
replace
only replace the first match. If wanna match all use global flag (g)
1
2
3
4
5
6
7
8
9
10
| const p =
'The quick brown fox jumps over the lazy dog. If the dog reacted, was it really lazy?';
const regex = /dog/gi;
console.log(p.replace(regex, 'ferret'));
// expected output: "The quick brown fox jumps over the lazy ferret. If the ferret reacted, was it really lazy?"
console.log(p.replace('dog', 'monkey'));
// expected output: "The quick brown fox jumps over the lazy monkey. If the dog reacted, was it really lazy?"
|
replaceAll
using a regexp you must have to set the global (“g”) flag;
1
2
3
4
5
6
7
8
9
10
| const p =
'The quick brown fox jumps over the lazy dog. If the dog reacted, was it really lazy?';
const regex = /dog/gi;
console.log(p.replaceAll(regex, 'ferret'));
// expected output: "The quick brown fox jumps over the lazy ferret. If the ferret reacted, was it really lazy?"
console.log(p.replaceAll('dog', 'monkey'));
// expected output: "The quick brown fox jumps over the lazy monkey. If the monkey reacted, was it really lazy?"
|
search
1
2
3
4
5
6
7
8
9
10
11
| const paragraph =
'The quick brown fox jumps over the lazy dog. If the dog barked, was it really lazy?';
// any character that is not a word character or whitespace
const regex = /[^\w\s]/g;
console.log(paragraph.search(regex));
// expected output: 43
console.log(paragraph[paragraph.search(regex)]);
// expected output: "."
|
slice
1
2
3
4
5
6
7
8
9
10
11
12
13
| const str = 'The quick brown fox jumps over the lazy dog.';
console.log(str.slice(31));
// expected output: "the lazy dog."
console.log(str.slice(4, 19));
// expected output: "quick brown fox"
console.log(str.slice(-4));
// expected output: "dog."
console.log(str.slice(-9, -5));
// expected output: "lazy"
|
split
1
2
3
4
5
6
7
8
9
10
11
12
13
| const str = 'The quick brown fox jumps over the lazy dog.';
const words = str.split(' ');
console.log(words[3]);
// expected output: "fox"
const chars = str.split('');
console.log(chars[8]);
// expected output: "k"
const strCopy = str.split();
console.log(strCopy);
// expected output: Array ["The quick brown fox jumps over the lazy dog."]
|
substring
1
2
3
4
5
6
7
| const str = 'Mozilla';
console.log(str.substring(1, 3));
// expected output: "oz"
console.log(str.substring(2));
// expected output: "zilla"
|
toLocaleLowerCase
1
2
3
4
5
6
7
| const dotted = 'İstanbul';
console.log(`EN-US: ${dotted.toLocaleLowerCase('en-US')}`);
// expected output: "i̇stanbul"
console.log(`TR: ${dotted.toLocaleLowerCase('tr')}`);
// expected output: "istanbul"
|
toLocaleUpperCase
1
2
3
4
5
6
7
| const city = 'istanbul';
console.log(city.toLocaleUpperCase('en-US'));
// expected output: "ISTANBUL"
console.log(city.toLocaleUpperCase('TR'));
// expected output: "İSTANBUL"
|
toLowerCase
1
2
3
4
| const sentence = 'The quick brown fox jumps over the lazy dog.';
console.log(sentence.toLowerCase());
// expected output: "the quick brown fox jumps over the lazy dog."
|
toUpperCase
1
2
3
4
| const sentence = 'The quick brown fox jumps over the lazy dog.';
console.log(sentence.toUpperCase());
// expected output: "THE QUICK BROWN FOX JUMPS OVER THE LAZY DOG."
|
toString
1
2
3
4
5
6
7
| const stringObj = new String('foo');
console.log(stringObj);
// expected output: String { "foo" }
console.log(stringObj.toString());
// expected output: "foo"
|
trim
1
2
3
4
5
6
7
| const greeting = ' Hello world! ';
console.log(greeting);
// expected output: " Hello world! ";
console.log(greeting.trim());
// expected output: "Hello world!";
|
trimEnd
1
2
3
4
5
6
7
| const greeting = ' Hello world! ';
console.log(greeting);
// expected output: " Hello world! ";
console.log(greeting.trimEnd());
// expected output: " Hello world!";
|
trimStart
1
2
3
4
5
6
7
| const greeting = ' Hello world! ';
console.log(greeting);
// expected output: " Hello world! ";
console.log(greeting.trimStart());
// expected output: "Hello world! ";
|
trimLeft
alias of trimStart()
trimRight
alias of trimEnd()
valueOf
1
2
3
4
5
6
7
| const stringObj = new String('foo');
console.log(stringObj);
// expected output: String { "foo" }
console.log(stringObj.valueOf());
// expected output: "foo"
|