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@joepie91
joepie91 / random.md
Last active November 16, 2024 19:07
Secure random values (in Node.js)

Not all random values are created equal - for security-related code, you need a specific kind of random value.

A summary of this article, if you don't want to read the entire thing:

  • Don't use Math.random(). There are extremely few cases where Math.random() is the right answer. Don't use it, unless you've read this entire article, and determined that it's necessary for your case.
  • Don't use crypto.getRandomBytes directly. While it's a CSPRNG, it's easy to bias the result when 'transforming' it, such that the output becomes more predictable.
  • If you want to generate random tokens or API keys: Use uuid, specifically the uuid.v4() method. Avoid node-uuid - it's not the same package, and doesn't produce reliably secure random values.
  • If you want to generate random numbers in a range: Use random-number-csprng.

You should seriously consider reading the entire article, though - it's

@Avaq
Avaq / combinators.js
Last active September 26, 2024 18:53
Common combinators in JavaScript
const I = x => x
const K = x => y => x
const A = f => x => f (x)
const T = x => f => f (x)
const W = f => x => f (x) (x)
const C = f => y => x => f (x) (y)
const B = f => g => x => f (g (x))
const S = f => g => x => f (x) (g (x))
const S_ = f => g => x => f (g (x)) (x)
const S2 = f => g => h => x => f (g (x)) (h (x))
@lukehoban
lukehoban / asyncloops.js
Last active May 31, 2021 23:18
Async/await and parallel loops
// ES6 w/ Promises
// Note: From a React starter template - see https://t.co/wkStq8y3I5
function fetchData(routes, params) {
let data = {};
return Promise.all(routes
.filter(route => route.handler.fetchData)
.map(route => {
return route.handler.fetchData(params).then(resp => {
data[route.name] = resp;
@tony-landis
tony-landis / recurse_image_optimize.sh
Created October 18, 2012 01:36
Recursively Optimize JPGs and PNGs using PNGCRUSH and JPEGTRAN
#!/bin/sh
# script for optimizing images in a directory (recursive)
# pngcrush & jpegtran settings from:
# http://developer.yahoo.com/performance/rules.html#opt_images
# pngcrush
for png in `find . | grep .png`; do
echo "crushing $png ..."
pngcrush -rem alla -reduce -brute "$png" temp.png