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daily JS drops. learning in public

[dev @noobdev89]

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[dev @noobdev89]

const numbers = [1, 3, 4];

const hasEven = numbers.some(n => n % 2 === 0);

console.log(hasEven); // true

[1, 3, 5].some(n => n % 2 === 0); // false

#DailyJS #Day30 #frontend #javascript

[dev @noobdev89]

daily js - every vs some

every returns true only if every item matches the condition
some returns true if atleast one item matches the condition

const numbers = [2, 4, 6];

[2,4,6].every(n => n % 2 === 0); //true

[2, 3, 6].every(n => n % 2 === 0); //false

(1/2)

[dev @noobdev89]

daily js - includes vs some

some checks if any of the item matches the condition

includes checks if the item is present in the array

const nums = [1, 2, 3];

nums.some(n => n > 2); // true
nums.includes(2); // true

#day29 #frontend #dailyjs #javascript

[dev @noobdev89]

daily js - includes vs find

includes checks if the value is present in the array, returns true or false

find returns the first item matching the condition

const nums = [1, 2, 3, 4];

nums.includs(1) - true
nums.find(n => n>2) - 3

#day28 #frontend #dailyjs #javascript

[dev @noobdev89]

daily js : == vs ===

== : compares values only
=== : compares value and type

0 == "0" // true
0 === "0" // false

#Day27 #frontend #dailyjs #javascript

[dev @noobdev89]

daily js - undefined vs null

undefined - JS says: “value not assigned yet”
null - Developer says: “I’m intentionally setting this to nothing”

#Day26 #frontend #dailyjs #javascript

[dev @noobdev89]

daily js - lazy loading

Loading a piece of code only when it is needed.

example:
home page loads first
profile page loads only when you open it

- faster page load
- smaller initial bundle

#Day25 #frontend #dailyjs #javascript

[dev @noobdev89]

how it works:

commonJS imports files when the code runs

if (true) {
const math = require("./math");
}

CommonJS loads modules at runtime using require() and shares code using module.exports.

#JavaScript #Day24 #WebDev #Frontend

[dev @noobdev89]

Daily JS - CommonJS

CommonJS is a way to share code between files in Node.js

Before browsers supported import/export, Node used CommonJS.

function add(a, b) {
return a + b;
}

module.exports = { add };

const { add } = require("./math");

add(2, 3); // 5

(1/2)

[dev @noobdev89]

Not 100% accurate - listen to online / offline events for reliability. because, it shows true eventhough wifi doesnot have internet

#WebDev #Day23 #Frontend #DailyJS

[dev @noobdev89]

Daily JS - https://t.co/cCB1nI9998

tells you if the browser is online or offline.

Useful for showing offline UI, disabling actions, or retrying APIs.

(1/2)

[dev @noobdev89]

Daily JS - Webpack

Webpack is a module bundler
It takes many JS, CSS, and asset files and turns them into files browsers can load.

#JavaScript #WebDev #Frontend #Day22

[dev @noobdev89]

- sayHello is not inside p1 or p2
- it is added to Person.prototype
- javascript finds it using __proto__

prototype is a property of a function used to share methods across all its objects.

#Day21 #webdev #JavaScript #DailyJS #Frontend

[dev @noobdev89]

Daily JS - prototype

function Person(name) {
https://t.co/UsIGQIjnIG = name;
}

// method added to prototype
Person.prototype.sayHello = function () {
return "Hello " + https://t.co/UsIGQIjnIG;
};

const p1 = new Person("Test");
const p2 = new Person("User");

(1/2)

[dev @noobdev89]

This lookup process is called prototype chain

__proto__ is a hidden link that JavaScript uses to find missing properties.

#DailyJS #Day20 #JavaScript #WebDev

[dev @noobdev89]

Daily JS - __proto__

const animal = {
eats: true
};

const dog = {
name: "Buddy"
};

dog.__proto__ = animal;

console.log(dog.eats); // true

- Dog doesnot have eats
- JS checks dog.__proto__
- dog is pointing to animal

(1/2)

[dev @noobdev89]

It silently removes undefined and functions:

const data = {
name: "Test",
age: undefined,
login: () => "ok"
};

JSON.stringify(data);
// {"name":"Test"}

This matters in APIs, localStorage, debugging, and logs.

#WebDev #Day19 #Frontend #DailyJS

[dev @noobdev89]

Daily JS - JSON.stringify()

JS objects can’t be sent over the network or stored directly.
JSON.stringify() converts a JS value into a JSON string so it can be saved or sent.

const user = { name: "Test", age: 27 };
JSON.stringify(user);
// {"name":"Test","age":27}

(1/2)

[dev @noobdev89]

So setTimeout(0) simply pushes your code to the next macrotask, after the current stack + microtasks are done.
That’s why promises always beat timeouts.

Rule to remember:
Microtasks > setTimeout(0) - every single time

#DailyJS #WebDev

[dev @noobdev89]

Daily JS - setTimeout(0) Truth

setTimeout(fn, 0) does not run immediately and it does not wait for microtasks.

JavaScript always finishes all microtasks first (Promise.then, queueMicrotask) before touching setTimeout. (1/2)

#DailyJS #Frontend #Day18 #WebDev