9 Hidden JavaScript Features You Probably Don’t Know Exist

JavaScript has many hidden tricks that most developers don’t know yet. These 9 hidden JavaScript features can make coding easier and save your time a lot. Let’s explore all 9 amazing JavaScript secrets with us! Welcome to our blog and enhance your JS coding skills with our tutorials!

1. The ?? Nullish Coalescing Operator

?? helps when checking for null or undefined. It is better than || because it does not treat "" or 0 as false. Unlike ||, it only considers null and undefined as falsy values, making it safer for real data.

JavaScript Double Question Mark vs Or: A Comprehensive Guide

let username = "";
console.log(username || "Guest");  // Outputs: Guest 
console.log(username ?? "Guest");  // Outputs: "" 

Operator	Works On	Problem	Solution
||	Any falsy value	Treats "" and 0 as false	Not ideal for all cases
??	Only null or undefined	Safer for real values	Better choice

2. The ?. Optional Chaining Operator

No more TypeErrors when dealing with nested objects!

let user = { profile: { name: "Alice" } };
console.log(user.profile?.name);   // Outputs: Alice 
console.log(user.settings?.theme); // Outputs: undefined 

3. Object.hasOwn() – A Safer hasOwnProperty()

Object.hasOwn() is better and safer for checking if an object really owns a property.

const obj = { key: "value" };
console.log(Object.hasOwn(obj, "key")); // true 
console.log(Object.hasOwn(obj, "toString")); // false 

4. replaceAll() for String Replacements

Use replaceAll() to replace multiple matches easily.

let text = "banana apple banana orange";
console.log(text.replaceAll("banana", "grape"));
// Outputs: "grape apple grape orange"

5. The at() Method for Arrays and Strings

at() makes it easy to get the last item in an array.

const fruits = ["apple", "banana", "cherry"];
console.log(fruits.at(-1)); // Outputs: "cherry" 

6. Numeric Separators for Readable Numbers

Big numbers can be hard to read. _ makes them clearer.

const billion = 1_000_000_000;
console.log(billion); // Outputs: 1000000000 

7. structuredClone()Deep Copy Made Easy

Forget manual deep cloning—JavaScript now has a built-in way!

const obj = { name: "Alice", skills: ["JS", "React"] };
const clone = structuredClone(obj);
clone.skills.push("Node.js");
console.log(obj.skills); // Outputs: ["JS", "React"] 

8. groupBy() for Arrays (Coming Soon!)

Grouping array items will soon be super easy.

const items = ["apple", "banana", "grape", "blueberry"];
console.log(groupBy(items, (item) => item.length));
// Outputs: { 5: ["apple", "grape"], 6: ["banana"], 9: ["blueberry"] }

Bonus: Math.trunc() for Quick Integer Extraction

Math.trunc() removes decimals without rounding up or down!

console.log(Math.trunc(4.9)); // Outputs: 4 
console.log(Math.trunc(-4.9)); // Outputs: -4 

Method	Input	Output	Remarks
Math.trunc()	4.9	4	Removes decimals without rounding
Math.trunc()	-4.9	-4	Same behavior for negative numbers
Math.floor()	4.9	4	Rounds down to the nearest integer
Math.ceil()	4.1	5	Rounds up to the nearest integer
Math.round()	4.5	5	Rounds to the nearest integer

Frequently Asked Questions (FAQ)

Conclusion

JavaScript has many hidden tricks that can save time and make coding fun. Try them out and let us know which one is your favorite!

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