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Post #2738
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Channel Public Channel
JA JavaScript
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Showing posts older than #2739 · Back to latest
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Post #2737
3.8K
CHALLENGE
class EventManager {
constructor() {
this.listeners = new Map();
}
addListener(event, callback) {
if (!this.listeners.has(event)) {
this.listeners.set(event, new Set());
}
this.listeners.get(event).add(callback);
}
removeAllListeners() {
this.listeners.clear();
}
}
const manager = new EventManager();
const obj = { data: new Array(1000).fill('memory') };
manager.addListener('test', () => obj.data.length);
manager.removeAllListeners();
console.log(manager.listeners.size); Post #2736
3.51K
- 🤔 8
- ❤ 3
- 👍 3
Post #2735
3.89K
CHALLENGE
const Maybe = {
of: (value) => ({ value, map: f => value == null ? Maybe.nothing() : Maybe.of(f(value)) }),
nothing: () => ({ value: null, map: () => Maybe.nothing() })
};
const result = Maybe.of(5)
.map(x => x * 2)
.map(x => x > 15 ? null : x)
.map(x => x + 1)
.map(x => x.toString());
console.log(result.value);- 🤔 8
- ❤ 4
- 👍 2
Post #2734
3.99K
A minimal CheatEngine implementation built with Rust and a terminal UI.
Do you think it’s possible to create something similar with JavaScript?
Do you think it’s possible to create something similar with JavaScript?
- 👍 4
- ❤ 2
- 🤔 2
- 🔥 1
Post #2733
3.95K
- ❤ 5
- 🔥 2
- 👍 1
Post #2732
4.26K
CHALLENGE
function Vehicle(type) {
this.type = type;
}
Vehicle.prototype.describe = function() {
return `This is a ${this.type}`;
};
function Car(brand) {
Vehicle.call(this, 'car');
this.brand = brand;
}
Car.prototype = Object.create(Vehicle.prototype);
Car.prototype.constructor = Car;
Car.prototype.describe = function() {
return Vehicle.prototype.describe.call(this) + ` made by ${this.brand}`;
};
const tesla = new Car('Tesla');
console.log(tesla.describe());
console.log(tesla.constructor.name);- ❤ 5
Post #2731
4.54K
🤟 Node.js v25.0.0 (Current) Released
The latest cutting edge version of Node has arrived with Web Storage enabled by default, JSON.stringify perf improvements, a new --allow-net option in the permission model, built-in Uint8Array base64/hex conversion, and WebAssembly and JIT optimizations. As shown in the diagram above, this means Node 24 will soon be promoted to being the 'active' LTS release and Node 22 will enter its 'maintenance' LTS phase.
Rafael Gonzaga
The latest cutting edge version of Node has arrived with Web Storage enabled by default, JSON.stringify perf improvements, a new --allow-net option in the permission model, built-in Uint8Array base64/hex conversion, and WebAssembly and JIT optimizations. As shown in the diagram above, this means Node 24 will soon be promoted to being the 'active' LTS release and Node 22 will enter its 'maintenance' LTS phase.
Rafael Gonzaga
- 👍 12
- ❤ 5
- 🔥 1
Post #2730
4.64K
- 👍 3
- ❤ 2
Post #2729
4.53K
CHALLENGE
const numbers = [1, 2, 3, 4, 5];
const pipeline = (...fns) => (value) => fns.reduce((acc, fn) => fn(acc), value);
const multiply = (x) => (y) => x * y;
const add = (x) => (y) => x + y;
const square = (x) => x * x;
const transform = pipeline(
multiply(2),
add(3),
square
);
const result = numbers.map(transform);
console.log(result);
- 👍 6
- ❤ 3
Post #2728
4.46K
- 👍 5
- 🔥 2
- 🤔 2
- ❤ 1
Post #2727
4.26K
CHALLENGE
const data = '{"name": "Maria", "age": 25, "skills": ["JavaScript", "Python"]}';
try {
const parsed = JSON.parse(data);
const modified = {
...parsed,
age: parsed.age + 5,
skills: [...parsed.skills, "TypeScript"]
};
const serialized = JSON.stringify(modified, null, 0);
const reparsed = JSON.parse(serialized);
console.log(reparsed.skills.length);
console.log(typeof reparsed.age);
} catch (error) {
console.log('Parse error');
}- ❤ 7
Post #2726
3.61K
- 🔥 3
- ❤ 2
- 👍 1
Post #2725
3.98K
CHALLENGE
const wm = new WeakMap();
const obj1 = {};
const obj2 = {};
const obj3 = obj1;
wm.set(obj1, 'first');
wm.set(obj2, 'second');
wm.set(obj3, 'third');
console.log(wm.get(obj1));
console.log(wm.get(obj2));
console.log(wm.get(obj3));
console.log(wm.has(obj1));
console.log(wm.size);
Post #2724
4.27K
- ❤ 4
- 🔥 3
- 👍 2
Post #2723
3.8K
CHALLENGE
const userInput = "<script>alert('xss')</script>";
const sanitized = userInput
.replace(/</g, '<')
.replace(/>/g, '>')
.replace(/"/g, '"')
.replace(/'/g, ''');
const credentials = {
username: 'admin',
password: 'secret123'
};
const safeLog = (obj) => {
const { password, ...safe } = obj;
return JSON.stringify(safe);
};
console.log(sanitized);
console.log(safeLog(credentials)); Post #2722
3.97K
- ❤ 3
Post #2721
4.09K
CHALLENGE
const a = 9007199254740991n;
const b = BigInt(9007199254740991);
const c = 9007199254740992;
const d = BigInt(9007199254740992);
console.log(a === b);
console.log(Number(a) === c);
console.log(c === Number.MAX_SAFE_INTEGER + 1);
console.log(d > a);
console.log(typeof (a + 1n));
console.log(Number(d) === c);
- ❤ 1
Post #2720
4.48K
👍 The Firefox team has put together a way for you to give input on which Interop proposals matter the most to you (above). Go to the Interop Feature Ranking site (GitHub account required) and drag the web platform features that matter most for you to the top.
- ❤ 5
- 👍 1
- 🔥 1
Post #2719
4.26K
- ❤ 5
- 👍 1
- 🔥 1