JavaScript

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❓ CHALLENGE

const weakMap = new WeakMap();
const arr = [1, 2, 3].map(n => ({ n }));

arr.forEach(obj => weakMap.set(obj, obj.n * 2));

arr.pop(); // Remove the last element

const result = arr.reduce((acc, obj) => acc + weakMap.get(obj), 0);

console.log(result);

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✌️ Regexes Got Good: The History (and Future) of Regular Expressions in JavaScript

Regular expression support was always a little underwhelming in JS, but things have improved. Steven takes us on a tour to refresh our knowledge, as well as show off his ‘regex’ library that boosts JS regexes to a true A++ rating. Steven was co-author of O’Reilly’s Regular Expressions Cookbook and High Performance JavaScript so knows his stuff.

Steven Levithan

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🔥 Billionaire Pavel Durov arrested... The truth about Telegram

Fireship

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❓ CHALLENGE

const obj1 = {
  name: "Alice",
  age: 25
};

const obj2 = {
  age: 30,
  city: "Wonderland"
};

with (obj1) {
  with (obj2) {
    name = "Bob";
    console.log(name, age);
  }
}

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❓ CHALLENGE

const obj = {
  a: 1,
  b: 2
};

let a = 10;
let b = 20;

with (obj) {
  a += 1;
  b += 1;
}

console.log(a, obj.a, b, obj.b);

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🌲 Node.js Security release process

Only those who have been involved in a security release process know how hard it is (time-consuming, effort).
We've been working hard to automate most (if not all) of the process and the new security release process is live

Rafael Gonzaga

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✌️ JavaScript Weekly #​701

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❓ CHALLENGE

const weakMap = new WeakMap();
const objs = [{}, {}, {}];

objs.forEach((obj, index) => weakMap.set(obj, index + 1));

const result = objs.filter(obj => weakMap.has(obj)).map(obj => weakMap.get(obj) * 2);

console.log(result);

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👍 Volta 2.0: Install and Run JavaScript Tools Quickly

A long-standing Rust powered tool for installing and switching JavaScript related tools (like Node, TypeScript, Yarn, etc.) … “no matter the package manager, Node runtime, or OS.” GitHub repo.

Volta

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❓ CHALLENGE

const weakMap = new WeakMap();
const obj1 = {};
const obj2 = { key: 'value' };

weakMap.set(obj1, obj2);

const result = weakMap.get(obj1).key.split('').reverse().join('');

console.log(result);

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😆 What about JavaScript?

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❓ CHALLENGE

const weakMap = new WeakMap();
const array = [1, 2, 3];
const obj = {};

weakMap.set(obj, array);

const result = weakMap.get(obj).reduce((acc, val) => acc + val);

console.log(result);

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World Class Web Components

🔥 Google takes its biggest L ever... now a convicted monopolist

Fireship