What is the output?
Anonymous Quiz
11%
['Laptop']
26%
TypeError: Cannot read property 'push' of undefined
43%
['Book', 'Laptop']
21%
['Book']
👍6🤔2❤1🔥1
The creator of the Porffor JavaScript compiler talks about the various ways to make JavaScript faster to execute, before digging into Porffor’s approach.
Oliver Medhurst
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❤5👍3🔥1
CHALLENGE
const templateFn = (strings, ...values) => {
return strings.reduce((result, str, i) => {
const value = values[i] !== undefined ?
(typeof values[i] === 'number' ? values[i] * 2 : values[i]) : '';
return result + str + value;
}, '');
};
const num = 5;
const str = 'world';
const result = templateFn`Hello ${str}, ${num} times ${'!'}`;
console.log(result);👍5❤2
What is the output?
Anonymous Quiz
19%
Hello world, 10 times !undefined
30%
Hello world, 5 times !undefined
36%
Hello world, 10 times !
15%
Hello world, 5 times !
🤔6❤5👍4
A custom element that uses the CSS Custom Highlight API (supported by most modern browsers) for syntax highlighting so you don’t need to retreat to the age-old method of wrapping every token in spans.
André Ruffert
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👍5❤3🔥1
CHALLENGE
function processConfig(config) {
const settings = {
timeout: config.timeout ?? 1000,
retries: config.retries ?? 3,
logging: config.logging ?? false,
debug: config.debug || true
};
return settings;
}
const userConfig = {
timeout: 0,
retries: null,
logging: false,
debug: false
};
console.log(processConfig(userConfig));👍8❤1
CHALLENGE
const createMathOps = (base) => {
return {
add: (x) => base + x,
multiply: (x) => base * x
};
};
const createAdvancedMathOps = (base) => {
const basicOps = createMathOps(base);
return {
...basicOps,
square: () => basicOps.multiply(base),
addThenSquare: (x) => {
const added = basicOps.add(x);
return added * added;
}
};
};
const calculator = createAdvancedMathOps(5);
console.log(calculator.addThenSquare(3));👍7❤1
🤣21🤔17❤4
CHALLENGE
const obj = { name: 'Alice', age: 30 };
const handler = {
get(target, prop) {
return prop in target ? target[prop] : `Property '${prop}' doesn't exist`;
}
};
const proxy = new Proxy(obj, handler);
const descriptors = Object.getOwnPropertyDescriptors(obj);
Reflect.defineProperty(obj, 'city', {
value: 'New York',
enumerable: false
});
console.log(proxy.city, proxy.country);❤3🔥2
Adonis is a popular TypeScript-first 'batteries included' web framework with a rich set of features, and its developers say they’re “shifting gears” and stepping up with more frequent major releases. v7 promises a lot, including Node.js diagnostic channel support, a type-safe URL builder, a new encryption layer, first-class support for notifications and TanStack Query, plus more. You’re encouraged to give your feedback here.
Romain Lanz
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❤5🔥3👍2
CHALLENGE
const text = 'Today is 2023-12-31 and tomorrow is 2024-01-01';
const dateRegex = /(\d{4})-(\d{2})-(\d{2})/g;
let result = '';
let match;
while ((match = dateRegex.exec(text)) !== null) {
const [fullMatch, year, month, day] = match;
result += `${day}/${month}/${year.slice(2)} `;
}
console.log(result.trim());
❤5👍2
What is the output?
Anonymous Quiz
33%
31/12/23 01/01/24
35%
2023-12-31 2024-01-01
20%
31/12/2023 01/01/2024
13%
31/12/23
❤4🤔4👍1
CHALLENGE
function* counter() {
let count = 1;
while (true) {
const reset = yield count++;
if (reset) {
count = 1;
}
}
}
const gen = counter();
console.log(gen.next().value);
console.log(gen.next().value);
console.log(gen.next(true).value);
console.log(gen.next().value);👍6❤3
👍5❤3🔥1🤔1
CHALLENGE
function outer() {
console.log(typeof inner);
console.log(typeof inner2);
var inner = function() {
return 'Inside inner';
};
function inner2() {
return 'Inside inner2';
}
console.log(typeof inner);
console.log(typeof inner2);
}
outer();👍4❤1
What is the output?
Anonymous Quiz
29%
function function function function
35%
undefined undefined function function
13%
function undefined function function
22%
undefined function function function
👍5🔥3❤2🤔1
What’s New? — It’s that time of year again. The Ecma General Assembly has approved the ES2025 language specification, which you can read in full here if you have a gallon of coffee to hand — or you can enjoy Dr. Axel’s more succinct explainer instead.
Dr. Axel Rauschmayer
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❤7👍3🔥2🤔1
CHALLENGE
const numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
const result = numbers
.filter(num => num % 2 === 0)
.map(num => num * 2)
.reduce((acc, curr, idx, arr) => {
if (idx === arr.length - 1) {
return (acc + curr) / arr.length;
}
return acc + curr;
}, 0);
console.log(result);