Common Shorthand Techniques in JavaScript
3 min readJan 6, 2021
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