rauschma

Strings

String.prototype.*

None of the string methods modify this – they always return fresh strings.

• charAt(pos: number): string ^ES1

  Returns the character at index pos, as a string (JavaScript does not have a datatype for characters). str[i] is equivalent to str.charAt(i) and more concise (caveat: may not work on old engines).

VictorTaelin

async/await is just the do-notation of the Promise monad

CertSimple just wrote a blog post arguing ES2017's async/await was the best thing to happen with JavaScript. I wholeheartedly agree.

In short, one of the (few?) good things about JavaScript used to be how well it handled asynchronous requests. This was mostly thanks to its Scheme-inherited implementation of functions and closures. That, though, was also one of its worst faults, because it led to the "callback hell", an seemingly unavoidable pattern that made highly asynchronous JS code almost unreadable. Many solutions attempted to solve that, but most failed. Promises almost did it, but failed too. Finally, async/await is here and, combined with Promises, it solves the problem for good. On this post, I'll explain why that is the case and trace a link between promises, async/await, the do-notation and monads.

First, let's illustrate the 3 styles by implementing

MatthieuLemoine

const id         = '__JUNK__';
// Public key need to be in PKCS8 format
// ssh-keygen -e -m PKCS8 -f id_rsa.pub > id_rsa.pkcs8
const publicKey  = fs.readFileSync(path.join(__dirname, 'id_rsa.pkcs8'), { encoding : 'utf8' });
const privateKey = fs.readFileSync(path.join(__dirname, 'id_rsa'), { encoding : 'utf8' });

// Sign
const signer = crypto.createSign('RSA-SHA512');
signer.update(id);
const signature = signer.sign(privateKey, 'hex');

craigdallimore

Transduce

• Ramda - transduce

• Also see

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What is transduce? What is it for? This document is intended to help people (such as myself) who would be looking through the ramda docs, find transduce and have no idea if it would be a good fit for my current problem.

MatthieuLemoine

#!/bin/bash

sudo apt-get install git bc
sudo git clone https://github.com/letsencrypt/letsencrypt /opt/letsencrypt
sudo mkdir /var/www/letsencrypt
sudo chown www-data /var/www/letsencrypt

Avaq

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))