Modern JavaScript Functions — Destructured Parameters, async/await, Generators

hello@ghafoorsblog.com (AG Sayyed) — Thu, 03 Jul 2025 08:00:00 +0000

What changed in modern JavaScript

ES2015 and later releases changed how function bodies look in production code. This third post in the functions trio shows the modern features that have become table stakes: destructured parameters, async/await, generators, and tagged templates.

Foundations: Functions — the basics Internals: Closures, this, and higher-order patterns

Destructured parameters

Object destructuring turns a single options argument into a self-documenting signature.

 1// Before
 2function fetchPage(url, options) {
 3 const method = (options && options.method) || "GET";
 4 const retries = (options && options.retries) || 3;
 5 // ...
 6}
 7
 8// After
 9function fetchPage(url, { method = "GET", retries = 3 } = {}) {
10 // ...
11}

The trailing = {} is essential — without it, calling fetchPage("/users") would attempt to destructure undefined and throw.

Async on Ghafoor's Personal Blog

Modern JavaScript Functions — Destructured Parameters, async/await, Generators

What changed in modern JavaScript

Destructured parameters