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JavaScript arrow operator

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The arrow operator, also known as the “fat arrow” operator, is a shorthand syntax for defining functions in JavaScript. It was introduced in ECMAScript 6 (ES6) and is a concise alternative to the traditional function syntax.

(parameter1, parameter2, ...) => { 
  // function body 
}

Here’s an example of a simple arrow function that takes two parameters and returns their sum:

const add = (a, b) => {
  return a + b;
}

This is equivalent to the following traditional function definition:

function add(a, b) {
  return a + b;
}

JavaScript arrow operator example

Simple example code of an arrow function that uses the Array.prototype.map() method to double each element in an array:

<!DOCTYPE html>
<html>
  <body>    
    <script>
    const numbers = [1, 2, 3, 4, 5];

    const doubledNumbers = numbers.map(number => number * 2);

    console.log(doubledNumbers);

    </script>
  </body>
</html>

Output:

JavaScript arrow operator

There are several advantages to using the arrow operator in JavaScript:

  1. Conciseness: Arrow functions allow you to write shorter, more concise code. They eliminate the need for the function keyword, curly braces, and return statement when writing simple functions.
  2. Clarity: You can make your code more readable by providing a clear and concise syntax for defining functions.
  3. Implicit returns: Arrow functions with a single expression implicitly return the result of that expression. This can make your code even shorter and more concise.
  4. Lexical this: Arrow functions don’t have their own value, but instead inherit this from the enclosing scope. This can help avoid confusion and errors when dealing with nested functions or methods.
  5. No binding of this: Arrow functions don’t bind this, which means they are not affected by the bind(), call(), or apply() methods. This can make them more predictable and easier to reason about.

Conciseness

// Traditional function syntax
function multiply(a, b) {
  return a * b;
}

// Arrow function syntax
const multiply = (a, b) => a * b;

Clarity:

// Traditional function syntax
const isEven = function(number) {
  return number % 2 === 0;
}

// Arrow function syntax
const isEven = (number) => number % 2 === 0;

Implicit returns:

// Traditional function syntax
function square(n) {
  return n * n;
}

// Arrow function syntax
const square = n => n * n;

Lexical this:

const person = {
  name: "John",
  age: 30,
  sayHello: function() {
    console.log(`Hello, my name is ${this.name}`);
  },
  sayHelloArrow: () => {
    console.log(`Hello, my name is ${this.name}`); // this.name will be undefined
  }
}

person.sayHello(); // Output: Hello, my name is John
person.sayHelloArrow(); // Output: Hello, my name is undefined

No binding of this:

const counter = {
  count: 0,
  increment: function() {
    setInterval(() => {
      console.log(this.count++);
    }, 1000);
  }
}

counter.increment();

Comment if you have any doubts or suggestions on this JS operator topic.

Note: The All JS Examples codes are tested on the Firefox browser and the Chrome browser.

OS: Windows 10

Code: HTML 5 Version

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