Common Shorthand Techniques in JavaScript

Declaration of variables

// Longhand
let x = 1; 
let y = 2;
 
// Shorthand
let x = 1, y = 2;

Assigning values to multiple variables

// Longhand 
let a = 1;
let b = 2, c = 3; 
// Shorthand 
let [a, b, c] = [1, 2, 3];

Ternary operator

// Longhand 
let marks = 7; 
let result; 
if(marks >= 3.5){
 result = 'Pass'; 
} else { 
 result = 'Fail'; 
} 
//Shorthand 
let result = marks >= 3.5? 'Pass' : 'Fail';

Assigning default value

// Longhand 
let imagePath; 
let path = getImagePath(); 
if(path !== null && path !== undefined && path !== '') { 
  imagePath = path; 
} else { 
  imagePath = 'default.jpg'; 
} 
// Shorthand 
let imagePath = getImagePath() || 'default.jpg';

Short circuit evaluation

// Longhand 
if (isLoggedin) {
 goToHomepage(); 
} 
// Shorthand 
isLoggedin && goToHomepage();

The AND(&&) short circuit shorthand is more useful in React when you want to conditionally render a component. For example:

<> { this.state.isLoading && <Loading /> } </>

Swap two variables

let x = 'Hello', y = 55; 
// Longhand 
const temp = x; 
x = y; 
y = temp; 
// Shorthand 
[x, y] = [y, x];

Arrow Function

// Longhand 
function add(num1, num2) { 
   return num1 + num2; 
}
 
// Shorthand 
const add = (num1, num2) => num1 + num2;

Template Literals

// Longhand 
console.log('You got a missed call from ' + number + ' at ' + time); 
// Shorthand 
console.log(`You got a missed call from ${number} at ${time}`);

Multiple condition checking

// Longhand 
if (value === 1 || value === 'one' || value === 2 || value === 'two') { 
     // Execute some code 
} 
// Shorthand 1
if ([1, 'one', 2, 'two'].indexOf(value) >= 0) { 
    // Execute some code 
}
// Shorthand 2
if ([1, 'one', 2, 'two'].includes(value)) { 
    // Execute some code 
}

Object Property Assignment

let firstname = 'Abhay'; 
let lastname = 'Jain';
// Longhand
let obj = {firstname: firstname, lastname: lastname}; 
// Shorthand 
let obj = {firstname, lastname};

Repeat a string multiple times

// Longhand 
let str = ''; 
for(let i = 0; i < 5; i ++) { 
  str += 'Hello '; 
} 
console.log(str); // Hello Hello Hello Hello Hello 
// Shorthand 
'Hello '.repeat(5);

Exponent Power

// Longhand 
const power = Math.pow(4, 3); // 64 
// Shorthand 
const power = 4**3; // 64

Double NOT bitwise operator

// Longhand 
const floor = Math.floor(6.8); // 6 
// Shorthand 
const floor = ~~6.8; // 6

Max and Min number in an array

// Shorthand 
const arr = [2, 8, 15, 4]; 
Math.max(...arr); // 15 
Math.min(...arr); // 2

For loop

let arr = [10, 20, 30, 40]; //Longhand 
for (let i = 0; i < arr.length; i++) { 
  console.log(arr[i]); 
}
// Shorthand 
// for of loop 
for (const val of arr) { 
  console.log(val); 
} 
// for in loop 
for (const index in arr) { 
  console.log(`index: ${index} and value: ${arr[index]}`); 
}

Merging of arrays

let arr1 = [20, 30];
// Longhand 
let arr2 = arr1.concat([60, 80]); 
// [20, 30, 60, 80] 
// Shorthand 
let arr2 = [...arr1, 60, 80]; 
// [20, 30, 60, 80]

Get character from string

let str = 'jscurious.com'; 
// Longhand 
str.charAt(2); // c 
// Shorthand 
str[2]; // c