jamiebuilds

assert() (sometimes called invariant())

Instead of checks like:

if (value === null) {
  throw new Error("missing value")
}
doSomethingThatNeedsValue(value)

slikts

Why using the children prop makes React.memo() not work

I've recently ran into a pitfall of [React.memo()][memo] that seems generally overlooked; skimming over the top results in Google just finds it mentioned in passing in a [React issue][regit], but not in the [FAQ] or API [overview][react-api], and not in the articles that set out to explain React.memo() (at least the ones I looked at). The issue is specifically that nesting children defeats memoization, unless the children are just plain text. To give a simplified code example:

const Memoized = React.memo(({ children }) => (<div>{children}</div>));
// Won't ever re-render
<Memoized>bar</Memoized>
// Will re-render every time; the memoization does nothing

Beneboe

How to Setup Verified Commits

Quick guide on how to setup git signing. Information is aggregated from following sources:

• https://help.github.com/articles/signing-commits/
• https://help.github.com/articles/telling-git-about-your-signing-key/
• https://help.github.com/articles/generating-a-new-gpg-key/

JoeyBurzynski

58 bytes of CSS to look great nearly everywhere

When making this website, i wanted a simple, reasonable way to make it look good on most displays. Not counting any minimization techniques, the following 58 bytes worked well for me:

main {
  max-width: 38rem;
  padding: 2rem;
  margin: auto;
}

david-crespo

Download photos and videos you're tagged in on Facebook

Why

When you download an archive of your Facebook account, Facebook includes photos and videos you've uploaded, but not photos and videos you're tagged in that were uploaded by other people. This is a script to automatically download those.

Setup

This requires Python 3.

thchia

// Main
function combineReducers(reducerDict) {
  const _initialState = getInitialState(reducerDict);
  return function(state = _initialState, action) {
    return Object.keys(reducerDict).reduce((acc, curr) => {
      let slice = reducerDict[curr](state[curr], action);
      return { ...acc, [curr]: slice };
    }, state);
  };
}

daftAnorak

# !/bin/bash

FILES=`{ git diff --name-only HEAD; \
         git ls-files --others --exclude-standard; } \
  | grep '\.js$' \
  | grep -v '^.*exclude-folder.*$'`

node_modules/.bin/eslint $FILES -f table --color --quiet

datchley

React/Redux Style Guide

Table of Contents:

• React/Redux Style Guide
  • React Guidelines
    • Organization
    • Components
• Container Components

bonfire-diff-two-arrays?solution=function%20diff(arr1%2C%20arr2)%20%7B%0A%20%20var%20check%20%3D%20arr1%3B%0A%20%20var%20checker%20%3D%20arr2%3B%0A%20%20%0A%20%20var%20filtered1%20%3D%20check.filter(function(el)%20%7B%0A%20%20%20%20%20%20%20if(checke

// Bonfire: Diff Two Arrays
// Author: @benschac
// Challenge: http://www.freecodecamp.com/challenges/bonfire-diff-two-arrays?solution=function%20diff(arr1%2C%20arr2)%20%7B%0A%20%20var%20check%20%3D%20arr1%3B%0A%20%20var%20checker%20%3D%20arr2%3B%0A%20%20%0A%20%20var%20filtered1%20%3D%20check.filter(function(el)%20%7B%0A%20%20%20%20%20%20%20if(checker.indexOf(el)%20%3D%3D%20-1)%20%7B%0A%20%20%20%20%20%20%20%20%20return%20el%3B%0A%20%20%20%20%20%20%20%7D%0A%20%20%20%20%7D)%3B%0A%20%20%0A%20%20%20var%20filtered2%20%3D%20checker.filter(function(el)%20%7B%0A%20%20%20%20%20%20%20if(check.indexOf(el)%20%3D%3D%20-1)%20%7B%0A%20%20%20%20%20%20%20%20%20return%20el%3B%0A%20%20%20%20%20%20%20%7D%0A%20%20%20%20%7D)%3B%0A%20%20%0A%20%20return%20filtered1.concat(filtered2)%3B%0A%7D%0A%0A%0A%0A%0Adiff(%5B1%2C%202%2C%203%2C%205%5D%2C%20%5B1%2C%202%2C%203%2C%204%2C%205%5D)%3B%0A
// Learn to Code at Free Code Camp (www.freecodecamp.com)

function diff(arr1, arr2) {
  var check = arr1;
  var checker = arr2;
  
  var filtered1 =

johnpolacek

[alias]
	co = checkout
	cob = checkout -b
	coo = !git fetch && git checkout
	br = branch
	brd = branch -d
	brD = branch -D
	merged = branch --merged
	st = status
	aa = add -A .