String questions

In JavaScript, `JSON.parse()` is used to convert a JSON string into a JavaScript object, while `JSON.stringify()` is used to convert a JavaScript object into a JSON string. These methods are essential for working with JSON data, enabling the exchange of data between servers and web applications.

`Array.prototype.join` joins all elements of an array into a string, with elements separated by a specified separator. The default separator is a comma if none is provided. 

const arr = ['a', 'b', 'c'];
console.log(arr.join('-')); // 'a-b-c'

`String.prototype.indexOf` returns the index of the first occurrence of a specified value in a string. If the value is not found, it returns -1. 

const str = 'hello';
const index = str.indexOf('l');
console.log(index); // 2

`String.prototype.localeCompare` compares two strings in the current locale and returns a number indicating whether the calling string comes before, after, or is equal to the compared string. 

const str1 = 'apple';
const str2 = 'banana';
const result = str1.localeCompare(str2);
console.log(result); // -1 (str1 is less than str2)

`String.prototype.fontcolor` returns a string wrapped in HTML `<font>` tags with a specified color. This method is deprecated and should not be used in modern applications. 

const str = 'hello';
const coloredStr = str.fontcolor('red');
console.log(coloredStr); // '<font color="red">hello</font>'

`String.prototype.fontsize` returns a string wrapped in HTML `<font>` tags with a specified size. This method is deprecated and should not be used in modern applications. 

const str = 'hello';
const sizedStr = str.fontsize(7);
console.log(sizedStr); // '<font size="7">hello</font>'

`String.prototype.anchor` creates an HTML `<a>` element wrapping the string with a specified name attribute. This method is deprecated and should not be used in modern applications. 

const str = 'Click here';
const anchoredStr = str.anchor('top');
console.log(anchoredStr); // '<a name="top">Click here</a>'

`String.prototype.small` returns a string wrapped in HTML `<small>` tags. This method is deprecated and should not be used in modern applications. 

const str = 'hello';
const smallStr = str.small();
console.log(smallStr); // '<small>hello</small>'

`Array.prototype.toString` returns a string representation of the array by concatenating its elements with commas. It does not modify the original array. 

const arr = [1, 2, 3];
console.log(arr.toString()); // '1,2,3'

`String.prototype.toUpperCase` returns a new string with all characters converted to uppercase. 

const str = 'hello';
const upper = str.toUpperCase();
console.log(upper); // 'HELLO'

`String.prototype.replace` replaces the first occurrence of a substring or pattern (regular expression) with a new substring. To replace all occurrences, a global regular expression must be used. 

const str = 'hello world';
const newStr = str.replace('world', 'JavaScript');
console.log(newStr); // 'hello JavaScript'

`String.prototype.includes` checks if a string contains a specified substring. It returns `true` if the substring is found, otherwise `false`. 

const str = 'hello';
console.log(str.includes('ell')); // true
console.log(str.includes('world')); // false

`String.prototype.concat` combines multiple strings into one string. It does not modify the original strings but returns a new concatenated string. 

const str1 = 'hello';
const str2 = 'world';
const combined = str1.concat(' ', str2);
console.log(combined); // 'hello world'

`String.prototype.substr` extracts a substring from a string based on a starting index and length. It returns the extracted substring. 

const str = 'hello world';
const substr = str.substr(6, 5);
console.log(substr); // 'world'

`String.prototype.slice` extracts a section of a string and returns it as a new string, without modifying the original string. 

const str = 'hello';
const sliced = str.slice(1, 4);
console.log(sliced); // 'ell'

`String.prototype.endsWith` checks if a string ends with a specified substring and returns `true` if it does, otherwise `false`. 

const str = 'hello';
console.log(str.endsWith('lo')); // true
console.log(str.endsWith('he')); // false

`String.prototype.link` creates an HTML `<a>` element wrapping the string, which is used to create hyperlinks. This method is deprecated and should not be used in modern applications. 

const str = 'Click here';
const linkedStr = str.link('https://example.com');
console.log(linkedStr); // '<a href="https://example.com">Click here</a>'

`String.fromCharCode` returns a string created from the specified sequence of UTF-16 code units. It is used to convert code units to characters. 

const char = String.fromCharCode(65);
console.log(char); // 'A'

`String.prototype.startsWith` checks if a string starts with a specified substring and returns `true` if it does, otherwise `false`. 

const str = 'hello';
console.log(str.startsWith('he')); // true
console.log(str.startsWith('lo')); // false

`String.prototype.trim` removes whitespace from both ends of a string, but does not affect whitespace in the middle of the string. 

const str = '  hello  ';
const trimmed = str.trim();
console.log(trimmed); // 'hello'

`String.prototype.charAt` returns the character at a specified index in a string. If the index is out of range, it returns an empty string. 

const str = 'hello';
const char = str.charAt(1);
console.log(char); // 'e'

`String.prototype.match` retrieves the matches of a string against a regular expression. It returns an array of matches or `null` if no matches are found. 

const str = 'hello 123';
const matches = str.match(/\d+/);
console.log(matches); // ['123']

`String.prototype.search` searches a string for a match against a regular expression and returns the index of the first match. If no match is found, it returns -1. 

const str = 'hello 123'; 
const index = str.search(/\d+/); 
console.log(index); // 6 

`String.prototype.codePointAt` returns an integer representing the UTF-16 code unit at a specified index in a string. It is useful for dealing with Unicode characters. 

const str = '𠮷';
const codePoint = str.codePointAt(0);
console.log(codePoint); // 134071

`Array.prototype.join` joins all elements of an array into a string, with elements separated by a specified separator. The default separator is a comma if none is provided. 

const arr = ['a', 'b', 'c'];
console.log(arr.join('-')); // 'a-b-c'