JavaScript Tips And Tricks 🔥🚀⚡

A collection of JavaScript tips and tricks.

No particular order or path.

I add things as I discover them.

Check Codinghub.tips, too, for JavaScript tips. It's not my project but I like it. 🔥

TABLE OF CONTENTS

• JavaScript Tips And Tricks 🔥🚀⚡
• TABLE OF CONTENTS
• OPTIONAL CHAINING
• NULLISH COALESCING OPERATOR
• MERGE OBJECTS TOGETHER - SPREAD OPERATOR
• TWO WAYS TO CONVERT A STRING TO A CHARACTER ARRAY
• DEFAULT PARAMETERS
• FILTER UNIQUE VALUES / REMOVE DUPLICATE VALUES
• FILTER OUT FALSY VALUES
• REQUIRED PARAMETERS

OPTIONAL CHAINING

"Shorter and simpler expressions when accessing chained properties when the possibility exists that a reference may be missing." (Source: MDN)

const person = {
  name: "Catalin Pit",
  socialMedia: {
    twitter: "@catalinmpit",
    instagram: "@catalinmpit",
    linkedin: "@catalinmpit",
  },
  experience: "Junior",
  employed: true
};

if (person && person.socialMedia && person.socialMedia.twitter) {
  console.log(person.socialMedia.twitter);
}

// The same thing with optional chaining
if (person?.socialMedia?.twitter) {
  console.log(person.socialMedia.twitter); // outputs @catalinmpit
}

// or
console.log(person?.socialMedia?.twitter);

NULLISH COALESCING OPERATOR

"The nullish coalescing operator (??) is a logical operator that returns its right-hand side operand when its left-hand side operand is null or undefined, and otherwise returns its left-hand side operand." (Source: MDN)

const person = {
  name: "Catalin Pit",
  socialMedia: {
    twitter: "@catalinmpit",
    instagram: "@catalinmpit",
    linkedin: "@catalinmpit",
  },
  experience: "Junior",
  employed: true
};

console.log(person.socialMedia.facebook ?? 'No Facebook account found!'); // Outputs 'No Facebook account found!'
console.log(person.socialMedia.instagram ?? 'No Instagram account found!'); // Outputs '@catalinmpit'


/// Another example ///
let name;

console.log(name ?? 'No name assigned'); // Outputs 'No name assigned'

let name = 'Catalin Pit';

console.log(name ?? 'No name assigned'); // Outputs 'Catalin Pit'

MERGE OBJECTS TOGETHER - SPREAD OPERATOR

"Shallow-cloning (excluding prototype) or merging of objects is now possible using a shorter syntax than Object.assign()." (Source: MDN)

const user = {
  name: "Catalin Pit",
  role: "Junior Fullstack Developer",
  age: 23
};

const uses = {
  machine: "MacBook Pro 15 inch",
  editor: "VS Code",
  language: "JavaScript",
  phone: "Samsung Note 10"
};

const summary = {...user, ...uses};

console.log(summary); 

// Outputs //
const summary = {
  name: "Catalin Pit",
  role: "Junior Fullstack Developer",
  age: 23,
  machine: "MacBook Pro 15 inch",
  editor: "VS Code",
  language: "JavaScript",
  phone: "Samsung Note 10"
}

TWO WAYS TO CONVERT A STRING TO A CHARACTER ARRAY

These are two quick ways to convert your string to an array of characters.

const firstName = "Catalin";

const firstNameArr1 = firstName.split('');
console.log(firstNameArr1);

const firstNameArr2 = [...firstName];
console.log(firstNameArr2);

DEFAULT PARAMETERS

"Default function parameters allow named parameters to be initialized with default values if no value or undefined is passed." (Source: MDN)

function add(x = 1, y = 2) {
  return x + y;
}

add();       // Returns 3
add(10);    // Returns 12
add(5, 5); // Returns 10

FILTER UNIQUE VALUES / REMOVE DUPLICATE VALUES

"Set objects are collections of values. You can iterate through the elements of a set in insertion order. A value in the Set may only occur once; it is unique in the Set's collection." (Source: MDN)

// Strings
const names = ['Catalin', 'Catalin', 'Pit', 'Pit', 'Tom', 'Tom', 'John', 'John'];
const uniqueNames = [...new Set(names)];

console.log(uniqueNames); // Outputs ['Catalin', 'Pit', 'Tom', 'John']


// Numbers
const examScores = [50, 75, 100, 99, 95, 67, 43, 43, 43, 100, 99, 50, 50, 50, 50];
const uniqueExamScores = [...new Set(examScores)];

console.log(uniqueExamScores); // Outputs [50, 75, 100, 99, 95, 67, 43];

FILTER OUT FALSY VALUES

Remove falsy values such as null, undefined, 0, boolean and so on, from an array.

const myArray = ["Catalin", 1, "Macbook", false, true, "Car", "Peace", 191, false];

const filteredArray = myArray.filter(Boolean);

console.log(filteredArray) // Returns ["Catalin", 1, "Macbook", true, "Car", "Peace", 191]

REQUIRED PARAMETERS

Default parameters allows us to require an argument to be passed to the function.

We can create a function which throws an error and assign it as default value for required parameters.

const required = () => {
    throw new TypeError("You did not pass the required argument!");
};

const greet = (name = required()) => console.log(`Hello ${name}!`);

greet() // Returns "Uncaught TypeError: You did not pass the required argument!"
greet("Catalin Pit") // Returns "Hello Catalin Pit!"