creationix

module.exports = function () {
  // If there is an uncaught exception anywhre in your app, it will result in a proper 500 page.
  if (Math.random() < 0.3) throw new Error("Oops, my random is low");
  // They don't have to happen in the first tick either
  if (Math.random() < 0.2) return setTimeout(function () {
    throw new Error("Delayed random bites");
  });

  // If you throw an object, it will send a JSON document to the client
  if (Math.random() > 0.6) throw {Hello: request.url};

branneman

Better local require() paths for Node.js

Problem

When the directory structure of your Node.js application (not library!) has some depth, you end up with a lot of annoying relative paths in your require calls like:

const Article = require('../../../../app/models/article');

Those suck for maintenance and they're ugly.

Possible solutions

Raynos

Virtual DOM and diffing algorithm

There was a [great article][1] about how react implements it's virtual DOM. There are some really interesting ideas in there but they are deeply buried in the implementation of the React framework.

However, it's possible to implement just the virtual DOM and diff algorithm on it's own as a set of independent modules.

amitsaxena

    <script type="text/javascript">
        var timer;
        var heartbeat;
        var lastInterval;

        function clearTimers() {
            clearTimeout(timer);
            clearTimeout(heartbeat);
        }

amitsaxena

    <script type="text/javascript">
        var timer;

        window.addEventListener("pageshow", function(evt){
            clearTimeout(timer);
        }, false);

        window.addEventListener("pagehide", function(evt){
            clearTimeout(timer);
        }, false);

domenic

// This event emitter emits events, but reserves the right to publish events to
// for its creator. It uses a WeakMap for true encapsulation.

const eesToEventMaps = new WeakMap();

export default class EventEmitter {
    constructor(publisher) {
        const eventMap = Object.create(null);
        eesToEventMaps.set(this, eventMap);

dherman

JS dialects with ES6 Realms

This essay explains how the ES6 Realm API makes it possible to create robust language abstractions that allow hooking into the behavior of eval, and how this can be used to implement different dialects of JavaScript.

Example scenario: Crock's "default operator"

Imagine we want to add Doug Crockford's ?? operator, which acts like a short-circuiting logical OR operator, except instead of checking truthiness, it returns the first argument's value if the first argument is any value other than undefined.

Since it makes everything simpler and cleaner, I'm going to assume I can use do-expressions for the implementation. (They're looking good for ES7!) So with that said, when we "crockpile" EXPR1 ?? EXPR2 we

ifels

package main

import (
	"io"
	"net/http"
	"os/exec"
)

var (
	BUF_LEN = 1024

samvasko

var gulp = require('gulp');
var watchify = require('watchify');
var browserify = require('browserify');
var source = require('vinyl-source-stream');
var gutil = require('gulp-util');

gulp.task('editor', function () {
    var b = browserify();
    b.require('./sources/js/scribe.js', {expose: 'scribe'});
    b.transform({global: true}, 'deamdify');

domenic

async function* foo() {
  console.log("1");
  await Q.delay(1000);
  console.log("2");
  yield "a";
  console.log("3");
  await Q.delay(1000);
  console.log("4");
  yield "b";
}