JavaScript

What is the output?

Anonymous Quiz

23%

❤4👍2🔥1

159 voters2.17K views06:30

JavaScript

Interesting idea 🤔

I always thought that front-end development is much harder then backend, but I was having trouble to explain that idea to developers. Today I wanted to check the opinion of the LLM, so called the general expert's opinion.

Agreed that front-end is harder for humans, because backend scales mathematically, rule based, and it's not that hard to understand. It's just math...

Then I asked, to find a similar analogy for front-end. It nailed. BIOLOGY!
____
Backend scaling: like mathematics: you add more nodes, shard databases, optimize queries - the system grows by formulas and predictable rules.

Frontend change: like biology: small mutations (new device, new browser feature, new UX demand) create emergent, often chaotic behavior that must be adapted to case by case.
____
Biology is more difficult then mathematics — mathematics is rule-bound and deterministic, while biology is emergent, full of exceptions, context-dependent, and constantly changing.
That’s why front-end (biology-like) feels messier and harder for humans, even if backend (math-like) can be more abstractly deep.

Edgar Marukyan

🤔11👍10❤3

2.82K views11:04

JavaScript

CHALLENGE

const values = [null, undefined, '', 0, false, NaN];
const results = [];

for (let val of values) {
  results.push({
    value: val,
    boolean: !!val,
    string: String(val),
    number: Number(val)
  });
}

console.log(results[2].boolean);
console.log(results[3].string);
console.log(results[1].number);

❤4👍2

2.47K views06:31

JavaScript

What is the output?

Anonymous Quiz

❤3👍2🔥1

207 voters2.68K views06:31

JavaScript

New career opportunity on the rise!

😆

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🤣23🔥3❤2🤩2

2.3K views13:15

JavaScript

CHALLENGE

class StateMachine {
  constructor() {
    this.state = 'idle';
    this.transitions = {
      idle: { start: 'running' },
      running: { pause: 'paused', stop: 'stopped' },
      paused: { resume: 'running', stop: 'stopped' },
      stopped: { reset: 'idle' }
    };
  }
  
  transition(action) {
    const next = this.transitions[this.state]?.[action];
    if (next) this.state = next;
    return this.state;
  }
}

const sm = new StateMachine();
console.log(sm.transition('start'));
console.log(sm.transition('invalid'));
console.log(sm.transition('pause'));
console.log(sm.transition('resume'));
console.log(sm.transition('stop'));
console.log(sm.transition('reset'));

❤6👍1

2.36K views06:31

JavaScript

What is the output?

Anonymous Quiz

24%

start invalid pause resume stop reset

34%

running running running running stopped stopped

18%

running idle paused running stopped idle

24%

running running paused running stopped idle

❤2👍2🔥2

164 voters2.42K views06:31

JavaScript

Prototype pollution 🥃

Exposing the default prototype by calling unsafe recursive functions with untrusted data as input

Read ~20mins estimated

learn.snyk.io

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❤7👍3🔥2

2.2K views22:33

JavaScript

CHALLENGE

console.log('1');

setTimeout(() => console.log('2'), 0);

Promise.resolve().then(() => console.log('3'));

setTimeout(() => console.log('4'), 0);

Promise.resolve().then(() => {
  console.log('5');
  return Promise.resolve();
}).then(() => console.log('6'));

console.log('7');

2.14K views06:30

JavaScript

What is the output?

Anonymous Quiz

❤5👍3🤔1

222 voters2.04K views06:30

JavaScript

⚡️

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@devhelperai_bot

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❤3👍2🔥1

2.12K views13:33

JavaScript

CHALLENGE

const nums = [1, 2, 3];
const obj = { a: 1, b: 2, c: 3 };

function process(...args) {
  const [first, ...rest] = args;
  const { a, ...others } = obj;
  return { first, rest, a, others };
}

const result = process(...nums);
console.log(result.first);
console.log(result.rest.length);
console.log(result.others.b);
console.log(Object.keys(result.others).join(''));
console.log(result.a === nums[0]);

❤2👍1

1.98K views06:34

JavaScript

What is the output?

Anonymous Quiz

❤5🤔3👍2

177 voters2.06K views06:34

JavaScript

CHALLENGE

let obj = { name: 'Sarah', age: 25 };
let weakMap = new WeakMap();
let map = new Map();

weakMap.set(obj, 'weak reference');
map.set(obj, 'strong reference');

console.log(weakMap.has(obj));
console.log(map.has(obj));

obj = null;

console.log(weakMap.has(null));
console.log(map.has(null));
console.log(map.size);

❤1

1.79K views06:34

JavaScript

What is the output?

Anonymous Quiz

31%

true true true true 1

39%

true true false false 1

21%

true true false false 0

false false false false 0

2❤2👍1🔥1

173 voters1.82K views06:34

JavaScript

CHALLENGE

function* fibonacci() {
  let [a, b] = [0, 1];
  while (true) {
    yield a;
    [a, b] = [b, a + b];
  }
}

function* takeWhile(generator, predicate) {
  for (const value of generator) {
    if (!predicate(value)) break;
    yield value;
  }
}

const fib = fibonacci();
const smallFibs = takeWhile(fib, x => x < 20);
console.log([...smallFibs].join(','));

❤1👍1

1.54K views06:32

JavaScript

What is the output?

Anonymous Quiz

🔥3❤2👍1

133 voters1.65K views06:32

JavaScript

🤟

Eliminating JavaScript Cold Starts on AWS Lambda

Porffor is a rapidly developing ahead-of-time JavaScript compiler with a major benefit being extremely quick process launch times (think sub-millisecond). This is certainly more a taste of the future, and something to experiment with, rather than something you want to imminently deploy into production.

Oliver Medhurst

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👍5❤3🔥1

1.37K views16:51

JavaScript

CHALLENGE

const user = {
  name: 'Sarah',
  age: 25,
  getName() { return this.name; },
  getAge: () => this.age
};

const methods = {
  regular: user.getName,
  arrow: user.getAge
};

console.log(methods.regular());
console.log(methods.arrow());
console.log(user.getName());
console.log(user.getAge());