CHALLENGE
const operations = {
value: 10,
multiply: function(x) {
return this.value * x;
},
arrow: (x) => {
return this.value * x;
},
nested: function() {
const inner = () => this.value * 2;
return inner();
}
};
console.log(operations.multiply(3));
console.log(operations.arrow(3));
console.log(operations.nested());👍6🔥4
❤2🔥2
CHALLENGE
class Calculator {
constructor(value) {
this.value = value;
}
add(num) {
this.value += num;
return this;
}
getValue = () => this.value;
}
const calc = new Calculator(10);
const addMethod = calc.add;
const getValueMethod = calc.getValue;
addMethod.call({value: 5}, 3);
console.log(calc.getValue());
console.log(getValueMethod());❤5👍2🔥2🤩2
👍3❤2
A smooth, fast way to browse packages on the official npm registry. It’s certainly fast, smooth, and you see more info up front and center - check out the axios page for example. “We’re not replacing the npm registry, but instead providing an elevated developer experience through a fast, modern UI.”
npmx
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🔥5❤2👍2🤣1
CHALLENGE
const wm = new WeakMap();
const obj1 = { name: 'Sarah' };
const obj2 = { name: 'Mike' };
wm.set(obj1, 'developer');
wm.set(obj2, 'designer');
console.log(wm.get(obj1));
console.log(wm.has(obj2));
console.log(wm.get({ name: 'Sarah' }));
console.log(wm.delete(obj1));
console.log(wm.has(obj1));
❤4🔥2👍1
A fun technical exploration of Symbol.dispose and using, two new features that’ll ease many headaches around cleaning up after yourself: closing connections, freeing resources, etc. Just watch out for the Muppets…
Mat Marquis
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❤5👍5🔥2
CHALLENGE
const cache = new Map();
function memoize(fn) {
return function(...args) {
const key = JSON.stringify(args);
if (cache.has(key)) {
return cache.get(key);
}
const result = fn(...args);
cache.set(key, result);
return result;
};
}
const fibonacci = memoize((n) => {
if (n <= 1) return n;
return fibonacci(n - 1) + fibonacci(n - 2);
});
console.log(fibonacci(5));
console.log(cache.size);
❤9🔥2👍1
❤5🔥3👍2
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❤5👍5🔥2
This is how the new generation learns about the Node.js EventLoop 😂
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❤11👍6🤣4🔥3
CHALLENGE
class CustomError extends Error {
constructor(message) {
super(message);
this.name = this.constructor.name;
}
}
try {
throw new CustomError("Something went wrong");
} catch (error) {
console.log(error.name);
console.log(error instanceof Error);
console.log(error instanceof CustomError);
console.log(typeof error.stack);
}❤8👍6🔥6
What is the output?
Anonymous Quiz
37%
CustomError true true string
40%
CustomError true true undefined
16%
Error true false string
7%
CustomError false true undefined
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👍6🔥4❤3
CHALLENGE
function createUser(name = 'Guest', age = 0, active = true) {
return { name, age, active };
}
const users = [
createUser('Sarah', 25),
createUser('Mike'),
createUser('Emma', undefined, false),
createUser(null, 30)
];
console.log(users.map(u => `${u.name}-${u.age}-${u.active}`).join('|'));❤3👍2
Does 50% memory savings in production sound good? Cloudflare, Igalia, and the Node project have collaborated on node-caged, a Docker image containing Node 25 with V8 pointer compression enabled. Matteo digs into all the details here – this is neat work, though there are tradeoffs to consider.
Matteo Collina
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CHALLENGE
const user = {
name: 'Sarah',
age: 25,
greet() {
return `Hello, I'm ${this.name}`;
}
};
const keys = Object.keys(user);
const values = Object.values(user);
const entries = Object.entries(user);
console.log(keys.length);
console.log(values.includes('Sarah'));
console.log(entries[2][0]);🔥6❤4👍2