Multi-threaded JavaScript

Web Assembly (WASM)

• example: Figma
  • the menus are in React
  • the main body is in Rust

Web workers

Web worker vs main thread

• no access to DOM
• can still fetch(), setTimeout()

Service workers

Web workers vs service workers

Generators

same as Python!

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

for (n of fibonacci()) {
    if (n > 100) break;
    console.log(n);
}

1
2
3
5
8
13
21
34
55
89

Generators before async/await

How async/await is implemented behind the scenes

Before async/await, you needed a library

var prom = require("bluebird");

var mongo = prom.promisifyAll(require("mongodb"));
var MongoClient = mongo.MongoClient;

var connectToMongo = prom.coroutine(function* () {
    var db = yield MongoClient.connect(mongoURL);
    return db;
});

var doMongo = prom.coroutine(function* () {
    var db = yield connectToMongo("mongodb://localhost:27017");
});

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Last update: 2023-04-24