Array methods

Method 12: String.startsWith() and String.endsWith() Methods

Array from() Method: It converts array-like or iterable objects into a new array with optional mapping function.
Array keys() Method: It provides an iterator for array indices, allowing iteration over keys/indices in an array.
Array find() Method: It locates and returns the first array element satisfying a provided condition.
Array findIndex() Method: It retrieves the index of the first array element satisfying a given condition.

Example: In this example we are using the above mentioned methods one by one.

Javascript

const languages = ["HTML", "CSS", "JavaScript", "React.js"]; 
  
// Using Array.from() to create a new array of lengths 
const lengths = Array.from(languages, lang => lang.length); 
console.log(lengths); // Outputs: [4, 3, 10, 7] 
  
// Using Array.keys() to iterate over array indices 
for (const index of languages.keys()) { 
    console.log(`Index ${index}: ${languages[index]}`); 
} 
  
// Using Array.find() to find the first language 
// with length greater than 5 
const longLanguage = languages.find(lang => lang.length > 5); 
console.log(longLanguage); // Outputs: "JavaScript" 
  
// Using Array.findIndex() to find the index of "React.js" 
const reactIndex = languages.findIndex( 
    lang => lang === "React.js"); 
      
console.log(reactIndex); // Outputs: 3

Output

[ 4, 3, 10, 8 ]
Index 0: HTML
Index 1: CSS
Index 2: JavaScript
Index 3: React.js
JavaScript
3

JS 2015 or ECMAScript 6 (ES6)

JS 2015 (ES6) also known as ECMAScript 6 (ES6), ECMAScript 6 (ES6) is a significant update to JavaScript, introducing arrow functions, classes, template literals, let and const for variable declaration, enhanced object literals, destructuring, and more modern features for better code organization and readability.

Array methods

Javascript

JS 2015 or ECMAScript 6 (ES6)

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