Nachasic

// testing using Jest
import { frac } from './frac';

describe('Math frac tests', () => {
    it('should be defined', () => {
        expect(frac).toBeDefined();
    });

    it('should accurately calculate fraction of a number', () => {
        expect( frac(-3.1234) ).toEqual( -0.1234 );

gaearon

Note:

When this guide is more complete, the plan is to move it into Prepack documentation.
For now I put it out as a gist to gather initial feedback.

A Gentle Introduction to Prepack (Part 1)

If you're building JavaScript apps, you might already be familiar with some tools that compile JavaScript code to equivalent JavaScript code:

• Babel lets you use newer JavaScript language features, and outputs equivalent code that targets older JavaScript engines.

ceejbot

ESM modules in node: npm edition

The proposal you’re about to read is not just a proposal. We have a working implementation of almost everything we discussed here. We encourage you to checkout and build our branch: our fork, with the relevant branch selected. Building and using the implementation will give you a better understanding of what using it as a developer is like.

Our implementation ended up differing from the proposal on some minor points. As our last action item before making a PR, we’re writing documentation on what we did. While I loathe pointing to tests in lieu of documentation, they will be helpful until we complete writing docs: the unit tests.

This repo also contains a bundled version of npm that has a new command, asset. You can read the documentation for and goals of that comma

jkeenan

How to Bisect a Problem in the Perl 5 Debugger

Bisection and the Perl 5 Core Distribution

Bisection is a developer's technique used to locate the point in a series of commits to a repository where the behavior of an application changed. While this change could be a change for the better -- "When did this feature start accidentally working?" -- the change being sought is usually a change for the worse: "When did this feature stop working correctly?".

ChrisPenner

const all = (...preds) => (obj) => preds.map(f => f(obj)).reduce((a, b) => a && b, true)
const any = (...preds) => (obj) => preds.map(f => f(obj)).reduce((a, b) => a || b, false)
const oneOf = (...preds) => (obj) => preds.map(f => f(obj)).reduce((a, b) => a ? !b : b, false)
const has = (prop) => (obj) => obj[prop] !== undefined
const not = (pred) => (obj) => !pred(obj)
const equals = (prop, val) => (obj) => obj[prop] === val
const implies = (f, g) => (obj) => !f(obj) || g(obj);

const validate = all(implies(has('selectedIndex'), equals('isOpen', true)))

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

egmontkob

Hyperlinks (a.k.a. HTML-like anchors) in terminal emulators

[ Update 2020-05-31: I won't be maintaining this page or responding to comments anymore (except for perhaps a few exceptional occasions). ]

---

Most of the terminal emulators auto-detect when a URL appears onscreen and allow to conveniently open them (e.g. via Ctrl+click or Cmd+click, or the right click menu).

It was, however, not possible until now for arbitrary text to point to URLs, just as on webpages.

2E0PGS

If your running a x64 bit Ubuntu or other Linux and find USB transfers hang at the end apply this fix:

echo $((16*1024*1024)) > /proc/sys/vm/dirty_background_bytes
echo $((48*1024*1024)) > /proc/sys/vm/dirty_bytes

I suggest you edit your /etc/rc.local file to make this change persistant across reboots.

sudo nano /etc/rc.local

kentcdodds

Faster JavaScript with SliceJS 🍕

This gist is for my talk Faster JavaScript.

Arinerron

#!/bin/bash

# Give the usual warning.
clear;
echo "[INFO] Automated Android root script started.\n\n[WARN] Exploit requires sdk module \"NDK\".\nFor more information, visit the installation guide @ https://goo.gl/E2nmLF\n[INFO] Press Ctrl+C to stop the script if you need to install the NDK module. Waiting 10 seconds...";
sleep 10;
clear;

# Download and extract exploit files.
echo "[INFO] Downloading exploit files from GitHub...";