Andrew's Blfog

Javascript generator functions

It has been a while since my last blog post!

I learned recently about generator functions, having successfully avoided them for over a decade. The basic idea in Javascript is that they are a function that returns a special iterable object. Iterable in this case meaning you can loop over it.

function* generatorFunctionOne () {
    yield "a";
    yield "b";
    yield "c";
    yield "d";

const g = generatorFunctionOne();

for (const yieldedItem of g) {

 * Logs, in order:
 * - a
 * - b
 * - c
 * - d

That's a rather contrived example, but more-or-less shows the base concept - each next call (or each iteration) will continue up to the next yield, and whatever that yield is will be provided as the iterable element, and can be repeated ad nauseum via a loop. So, for example, if you wanted to generate n random numbers...


NPM sucks

I always find frontend devs way of thinking to optimization interesting. Shaving few KBs of JavaScript but load dozens of MBs images. Then talking about avoiding dependencies but using node packages that indirectly pull in hundreds of other dependencies. Loading scripts from dozens of HTTP connections, etc.

~ some guy on the internet, July 2020

having to wrangle npm is a nightmare of dependencies that is never-ending with some packages.

it's ridiculously easy to upload npm packages, which leads to people creating dependencies for things like checking if a number is odd. Compartmentalizing things into reusable bits isn't really all that bad, but for some reason npm takes it to the extreme.