Slice and Split Strings

JavaScript provides several methods to extract and divide strings.

slice()

Extracts a portion of a string by start and end position:

let str = "Hello, World!";

str.slice(0, 5);     // "Hello"
str.slice(7);        // "World!" (from position 7 to end)
str.slice(-6);       // "orld!" (from 6th-to-last)
str.slice(0, -1);    // "Hello, World" (remove last char)

substring()

Similar to slice but doesn't accept negative indices:

let str = "Hello, World!";

str.substring(0, 5);   // "Hello"
str.substring(7);      // "World!"
str.substring(7, 12);  // "World"

split()

Splits a string into an array based on a delimiter:

let csv = "apple,banana,cherry,date";
let fruits = csv.split(",");
console.log(fruits);  // ["apple", "banana", "cherry", "date"]

let sentence = "Hello World JavaScript";
let words = sentence.split(" ");
console.log(words);   // ["Hello", "World", "JavaScript"]

// Split every character
let chars = "Hello".split("");
console.log(chars);   // ["H", "e", "l", "l", "o"]

Combining split() and join()

// Replace spaces with dashes
let title = "Hello World JavaScript";
let slug = title.toLowerCase().split(" ").join("-");
console.log(slug);  // "hello-world-javascript"

// Reverse a string
let reversed = "Hello".split("").reverse().join("");
console.log(reversed);  // "olleH"

repeat()

let star = "⭐";
console.log(star.repeat(5));  // "⭐⭐⭐⭐⭐"

let line = "-".repeat(30);
console.log(line);  // "------------------------------"