This content originally appeared on DEV Community and was authored by Palash Mondal
Hi everyone ?
Today I wanted to share with you 10 awesome JavaScript shorthands that will increase your speed by helping you to write less code and do more.
Let's start!
1. Merge Arrays
Longhand:
We usually merge two arrays using Array concat() method. The concat() method is used to merge two or more arrays. This method does not change the existing arrays but instead returns a new array. Here is a simple example:
let apples = ['?', '?'];
let fruits = ['?', '?', '?'].concat(apples);
console.log( fruits );
//=> ["?", "?", "?", "?", "?"]
Shorthand:
We can shorten this a bit by using ES6 Spread Operator (...) like this:
let apples = ['?', '?'];
let fruits = ['?', '?', '?', ...apples]; // <-- here
console.log( fruits );
//=> ["?", "?", "?", "?", "?"]
and we are still getting the same output as before. ?
2. Merge Arrays (but at the start)
Longhand:
Let's say we want to add all the items from the apples array at the start of fruits array, instead of at the end like we have seen in the last example. We can do this using Array.prototype.unshift() like this:
let apples = ['?', '?'];
let fruits = ['?', '?', '?'];
// Add all items from apples onto fruits at start
Array.prototype.unshift.apply(fruits, apples)
console.log( fruits );
//=> ["?", "?", "?", "?", "?"]
Now the two red & green apples are at the start instead of the end after merging.
Shorthand:
We can shorten this long code again using ES6 Spread Operator (...) like this:
let apples = ['?', '?'];
let fruits = [...apples, '?', '?', '?']; // <-- here
console.log( fruits );
//=> ["?", "?", "?", "?", "?"]
3. Clone Array
Longhand:
We can easily clone an array using the Array slice() method like this:
let fruits = ['?', '?', '?', '?'];
let cloneFruits = fruits.slice();
console.log( cloneFruits );
//=> ["?", "?", "?", "?"]
Shorthand:
Using ES6 Spread Operator (...) we can clone an array like this:
let fruits = ['?', '?', '?', '?'];
let cloneFruits = [...fruits]; // <-- here
console.log( cloneFruits );
//=> ["?", "?", "?", "?"]
4. Destructuring Assignment
Longhand:
While working with arrays, we sometimes need to "unpack" arrays into a bunch of variables like this:
let apples = ['?', '?'];
let redApple = apples[0];
let greenApple = apples[1];
console.log( redApple ); //=> ?
console.log( greenApple ); //=> ?
Shorthand:
We can achieve the same result in a single line using Destructuring assignment like this:
let apples = ['?', '?'];
let [redApple, greenApple] = apples; // <-- here
console.log( redApple ); //=> ?
console.log( greenApple ); //=> ?
5. Template literals
Longhand:
Usually, when we have to add an expression to a string we do it like:
// Display name in between two strings
let name = 'Palash';
console.log('Hello, ' + name + '!');
//=> Hello, Palash!
// Add & Subtract two numbers
let num1 = 20;
let num2 = 10;
console.log('Sum = ' + (num1 + num2) + ' and Subtract = ' + (num1 - num2));
//=> Sum = 30 and Subtract = 10
Shorthand:
With Template literals we can use backticks (`), which allow us to embed any expression into the string, by wrapping it in ${...} like this:
// Display name in between two strings
let name = 'Palash';
console.log(`Hello, ${name}!`); // <-- No need to use + var + anymore
//=> Hello, Palash!
// Add two numbers
let num1 = 20;
let num2 = 10;
console.log(`Sum = ${num1 + num2} and Subtract = ${num1 - num2}`);
//=> Sum = 30 and Subtract = 10
6. For Loop
Longhand:
Using the for loop we can loop through an array like this:
let fruits = ['?', '?', '?', '?'];
// Loop through each fruit
for (let index = 0; index < fruits.length; index++) {
console.log( fruits[index] ); // <-- get the fruit at current index
}
//=> ?
//=> ?
//=> ?
//=> ?
Shorthand:
We can achieve the same result using the for...of statement but with very little code like this:
let fruits = ['?', '?', '?', '?'];
// Using for...of statement
for (let fruit of fruits) {
console.log( fruit );
}
//=> ?
//=> ?
//=> ?
//=> ?
7. Arrow Functions
Longhand:
To loop through an array we can also use Array forEach() method. But we have to write a bit more code, which is less than the most common for loop we have seen above, but still a bit more than the for...of statement :
let fruits = ['?', '?', '?', '?'];
// Using forEach method
fruits.forEach(function(fruit){
console.log( fruit );
});
//=> ?
//=> ?
//=> ?
//=> ?
Shorthand:
But with Arrow function expressions we can write the full loop code in a single line like this:
let fruits = ['?', '?', '?', '?'];
fruits.forEach(fruit => console.log( fruit )); // <-- Magic ✨
//=> ?
//=> ?
//=> ?
//=> ?
I mostly use forEach loop with arrow functions, but I wanted to show you both the shorthand for looping: for...of statement and forEach loop. So that you can use whichever code you like based on your preference. ?
8. Find an object in an array
Longhand:
To find an object in an array of objects by one of its properties, we usually use for loop like this:
let inventory = [
{name: 'Bananas', quantity: 5},
{name: 'Apples', quantity: 10},
{name: 'Grapes', quantity: 2}
];
// Get the object with the name `Apples` inside the array
function getApples(arr, value) {
for (let index = 0; index < arr.length; index++) {
// Check the value of this object property `name` is same as 'Apples'
if (arr[index].name === 'Apples') { //=> ?
// A match was found, return this object
return arr[index];
}
}
}
let result = getApples(inventory);
console.log( result )
//=> { name: "Apples", quantity: 10 }
Shorthand:
Wow! We have to write so much previously, to implement this logic. But with Array find() method and arrow function =>, we can easily achieve this in one line like this:
// Get the object with the name `Apples` inside the array
function getApples(arr, value) {
return arr.find(obj => obj.name === 'Apples'); // <-- here
}
let result = getApples(inventory);
console.log( result )
//=> { name: "Apples", quantity: 10 }
9. Convert String to Integer
Longhand:
The parseInt() function is used to parse a string and return an integer:
let num = parseInt("10")
console.log( num ) //=> 10
console.log( typeof num ) //=> "number"
Shorthand:
We can achieve the same result by adding a + prefix before the string like this:
let num = +"10";
console.log( num ) //=> 10
console.log( typeof num ) //=> "number"
console.log( +"10" === 10 ) //=> true
10. Short-circuit Evaluation
Longhand:
Mostly if-else statement is used if we have to set a value based on another value is not a falsy value like this:
function getUserRole(role) {
let userRole;
// If role is not falsy value
// set `userRole` as passed `role` value
if (role) {
userRole = role;
} else {
// else set the `userRole` as USER
userRole = 'USER';
}
return userRole;
}
console.log( getUserRole() ) //=> "USER"
console.log( getUserRole('ADMIN') ) //=> "ADMIN"
Shorthand:
But using short-circuit evaluation (||), we can do this in one line like this:
function getUserRole(role) {
return role || 'USER'; // <-- here
}
console.log( getUserRole() ) //=> "USER"
console.log( getUserRole('ADMIN') ) //=> "ADMIN"
Basically, expression1 || expression2 is short-circuit evaluated to the truthy expression. So, it's like saying that if the first part is true don't bother evaluating the rest of the expression.
Finally, I would like to end this article by sharing one quote by Jeff Atwood:
Code is only our enemy because there are so many of us programmers writing so damn much of it. If you can’t get away with no code, the next best thing is to start with brevity.
If you love writing code — really, truly love to write code — you’ll love it enough to write as little of it as possible.
If you liked this article, be sure to ❤ it.
You can also checkout my previous blog:
Happy Coding!
This content originally appeared on DEV Community and was authored by Palash Mondal
Palash Mondal | Sciencx (2021-07-29T12:48:11+00:00) 10 Awesome JavaScript Shorthands. Retrieved from https://www.scien.cx/2021/07/29/10-awesome-javascript-shorthands/
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