A little fun with Javascript

Just playing around with the spread operator and I found a neat little design pattern I think I am going to work in:

let testArr = [9,1, 2, 6, 3, 4];
const newMax = (arr) => {
  if(arr.length === 1) { return console.log('end')};
  var [a, ...arr] = arr;
  let max = Math.max(a,...arr);
  console.log(max ,' >=', ...arr);
9 ' >=' 1 2 6 3 4
6 ' >=' 2 6 3 4
6 ' >=' 6 3 4
6 ' >=' 3 4
4 ' >=' 4

Seems a fun way to look for edges like in the water trap toy problem? I am not sure, but it will be fun to play around with it.

Another thing that used to annoy me was how you had to use string concatenation. It just looked so ugly. I finally (okay I am late to the party) started using backticks for multi-line parties!

var motion = `Le mouvement de lacet sur la berge des chutes du fleuve,
Le gouffre à l’étambot,
La célérité de la rampe,
L’énorme passade du courant
Mènent par les lumières inouïes
Et la nouveauté chimique
Le voyageurs entourés des trombes du val
Et du strom.`

And finally a little more fun with the spread operator (thanks Alex Rauschmayer) but you can make an array only contain unique values in a very clean, native way.

const arr = [7, 3, 1, 3, 3, 7];
[...new Set(arr)]
[ 7, 3, 1 ]

Front Ends… who needs em!

I have always preferred to work on the back end. It seems more peaceful there. The front end is all colors, moving stuff, and clicks!! Why should I care about clicks… I respond to requests no clickity click click demands! I am fine seeing JSON shoved on the screen, I will parse it visually, personally. I don’t need fancy filters, sorters and interfaces for data.

This opinion puts me most certainly in the minority, so as every good developer does, I forced myself to do something that made me uncomfortable, make a front end. A little background, the project is a way for me to organize my interviews. I needed a place to hold the questions, let me run through them, add notes, and rate the candidate etc.

The api was written with hapijs, my new personal favorite node framework. I was waffling about what to choose for the client side of things. I have already built a few things with Angular 1.5 so I was contemplating Angular 2, but that would go against the reason I am doing this in the first place. I mean if I am going to go out of my comfort zone, it might as well be way out. I could do it in pure vanilla js, but again I am quite familiar with that.. Come on John! Think… think… A-ha! React. I hear about it constantly. It seems to solve some issues with rendering speeds. It has cool terms like ShadowDOM and JSX that remind me of hackers and superbikes in a cyberpunk movie.

ShadowDOM leapt, turning mid-air. Using a neural link to control JSX superbike, it started just before her ass slammed into the seat and exploded violently forward…”

I am a few days in now. I have the basic CRUD working, and you know what? I don’t hate it! I like the way react apps come together. Nice and modular, with plenty of opportunity to build reusable components, really fun stuff. So I guess the lesson learned is to keep yourself confused and uncomfortable. Sounds like fun!


100% Code Coverage or Die!

I have been working on my next tutorial. It will be a hapi.js api (maybe even with a React/Redux client) as close to production quality as I can get without a different (aka better) hardware infrastructure. Quality error messages, logging, input validation, fully documented, authentication with scopes and most importantly testing with 100% code coverage.

This is what I am currently working on and it’s been interesting learning how Hapi.js gets tested and what differences configuration over coding makes in my approach. So far I like it even though I am struggling with some specific routes. It is always fun to learn something new and feel that struggle again. I certainly prefer to have to work at something for a bit over working on the same thing over and over again.

I should have something ready in the next few days, maybe a week! I swear I just love coding so much!


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Publishing an NPM Module Part 7

These are my notes based on the phenomenal tutorial by Kent C. Dodds hosted by egghead.io both of which are my go to sources when I want to learn something new. I highly suggest you sign up for the pro subscription.

Part 1 | Part 2 | Part 3 | Part 4 | Part 5 | Part 6 | >Part 7

Part 7: Making a Browser Build

Now what if we wanted to make it so a website could consume our nifty library? We could force them to create a node api to use our wonderful features. Or we could be nice and just let them load up via cdn! I think we should go that route. So first we need to install webpack the module bundler! In a nutshell webpack will take all of your various bits and bobs and package them up. So head to your project folder in your console and type:

$ npm i -D webpack

Now we need to create a basic config file for it.

import {join} from 'path'

const include = join(__dirname, 'src');

export default {
    entry:  './src/index',
    output: {
        path: join(__dirname, 'dist'),
        libraryTarget: 'umd',
        library: 'randomCharacterName',
    devtool: 'source-map',
    module: {
        loaders: [
            {test: /\.js$/, loader: 'babel', include},
            {test: /\.json$/, 'loader': 'json', include}

Entry is pretty simple, where do we look for the app? Output is also fairly self-explanatory, where do we put the distributed files and what do we do with them. Path is the place, libraryTarget is what format we will be exporting, in our case we are using umd and finally library is just the name of the library. The devtool section specifies a tool to help with debugging in our case we are using source-map to help us track down where errors are actually occurring.  The modules section allows us to use certain loaders. In our case we will be using babel load and json loader.  In fact we should probably install them!

$ npm i -D babel-loader json-loader

Now that those are in place we need to modify a few things in our package.json file. We are going to rename build to build:main, add build:umd and build:umd.min.

"build:main": "babel --copy-files --out-dir dist --ignore *.test.js src",
"build:umd": "webpack --output-filename index.umd.js",
"build:umd.min": "webpack --output-filename index.umd.min.js -p",

Go ahead and run:

$ npm run build:umd

Neat! Only problem now is how to we run all of these when we need to build again… There is a nifty package just for that called npm-run-all.

$ npm i -D npm-run-all

Now jump back to package.json and add in the new supercharged build script:

"build": "npm-run-all --parallel build:*",

Now after you have this all committed and pushed take a look at npmcdn.com/name-of-your-library. See mine for an example. You can go to a specific version by adding an @ to the end of the url and specifying the semver i.e. 1.6.0. You can also specify which one you want by adding a pointer to a specific file in your dist directory. 


All cool stuff! This is the conclusion of this tutorial. My next one will be building out an API, stay tuned.

glyphicons-55-clock  = Time Saving Idea

glyphicons-499-sunglasses = Pro Tip

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Publishing an NPM Module Part 6

These are my notes based on the phenomenal tutorial by Kent C. Dodds hosted by egghead.io both of which are my go to sources when I want to learn something new. I highly suggest you sign up for the pro subscription.

Part 1 | Part 2 | Part 3 | Part 4 | Part 5 | >Part 6 | Part 7

Part 6: Adding ES6 Support

We need to add babel-cli to our dev dependencies:

$ npm i -D babel-cli
glyphicons-28-search  The Docs 
Common uses:
babel -w -o  //watch for file changes and output
babel src -o  // compile entire src dir and concat
babel src -d lib //compile entire src dir and output to lib
babel --ignore  //add this to ignore files i.e. tests

Next we will add a build script for babel. Looking in our node_modules/bin we can see babel has been added making it available to npm for scripts. Let’s edit our package.json to include:

"build": "babel --out-dir dist src”

Now let’s test it to see what gets generated when we run our script. In your terminal run:

$ npm run build

Look in the dist directory and you will see that it was created and files were moved over. It also added our test files! This is something we don’t want to push to the dist since if we test when we publish, not when we consume. We can solve this by adding an ignore flag:

“build”: ''babel --out-dir dist --ignore *.test.js src"

Since this creates a dist directory with files in it, we want to make sure that if we make a change in a filename that the old one is not present in the next build in order to delete the directory cleanly we will add a prebuild script to package.json

"prebuild": "rm -rf dist”

However this is only *nix supported in order to allow windows devs to use this we must add a new dev package called rimraf  a cross-platform rm -rf built for node.

$ npm i -D rimraf

replace rm-rf with rimraf:

"prebuild": "rimraf dist”

now convert to es6 i.e.:

'use strict'
//require external dependencies
import uniqueRandomArray from 'unique-random-array';
import _ from 'lodash';

//define available data
import firstNames from '../data/first-names.json';
import middleNames from '../data/middle-names.json';
import lastNames from '../data/last-names.json';

//random generators
let randomFirstName = uniqueRandomArray(firstNames);
let randomMiddleName = uniqueRandomArray(middleNames);
let randomLastName = uniqueRandomArray(lastNames);

//filter functions
const filteredNames = function (nameList, initial) {
 return nameList.filter(function (name) {
 return name[0] === initial;

const list = ()=>{
 let allNames = ["FirstName MiddleName LastName"];
 for (var i = 0; i < firstNames.length; i++) {
 //Math.floor((Math.random() * 10) + 1);
 var tmpName = randomFirstName() + ' ' + randomMiddleName() + ' ' + randomLastName();
 return allNames;

const single = ()=>{
 return randomFirstName() + ' ' + randomMiddleName() + ' ' + randomLastName();

const startsWithLetter = (f, m, l)=>{
 var firstName = _.sample(filteredNames(firstNames, f));
 var middleName = _.sample(filteredNames(middleNames, m));
 var lastName = _.sample(filteredNames(lastNames, l));
 return firstName + ' ' + middleName + ' ' + lastName;

const numberOfNames = (number=1, allNames=[])=>{
 for (var i = 0; i < number; i++) {
 var tmpName = randomFirstName() + ' ' + randomMiddleName() + ' ' + randomLastName();
 return allNames;

//available methods
module.exports = {
 list: list,
 single: single,
 startsWithLetter: startsWithLetter,
 numberOfNames: numberOfNames

Now lets run our build script again:

$ npm run build

Now let’s take a look at index.js in dist and notice nothing happened! That is because really all we did was have it copy it over. We did not tell it to do anything! So we need to install some presets to tell babel how to do the transpiling:

npm i -D babel-preset-es2015 babel-preset-stage-2
glyphicons-28-search Learn more about presets

In order for babel to know about these presets we have added we need to change our package.json to reflect this:

"babel": {
  "presets": [



We need to change our package.json file to point to dist now:

"main": "dist/index.js",

While we are here we should update the build script by adding –copy-files:

"build:main": "babel --copy-files --out-dir dist --ignore *.test.js src",


Now we need to make sure the build script runs before the publish script. We do this by modifying the .travis.yml file scripts section, after check-coverage add:

- npm run build

Now we need to do a little verification on our changes. Let’s run a command to see what will actually be published:

$ npm pack   

A file was generated ending in tgz. Open that up and take a peek. It looks alright, but there are just some extra files in there that we might not need or want. So let’s learn how to limit what gets packed up. We do this by adding a files section to our package.json file:

"files": [

  Now that we are writing in ES6 we want to make sure that all of the other pieces are able to work with the new syntax as well. Let’s start with istanbul. It turns out we need a replacement package for that called nyc.

$ npm i -D nyc

Now we need to update package.json to use this new method:

"check-coverage": "nyc check-coverage --statements 100 --branches 100 --functions 100 --lines 100",

Next in the test with the watch command (-w) we want to add in something that will transpile our code. 

"test:watch": "mocha src/index.test.js --compilers js:babel-register -w",

Since we are using it we might as well install it!

npm i -D babel-register

The tests are getting a little clunky, with a lot of repeated code so we are going to clean things up a bit. by letting the watch test just fire off the regular test adding in a -w flag.

"test:watch": "npm t -- -w",
"test": "mocha src/index.test.js --compilers js:babel-register",

Note the double dash in the watch script. This allows you to send in the watch flag to the previous call as if it were in the original.  Since we are cleaning things up let’s go a little farther, but adding a cover script.

"cover": "nyc --reporter=lcov npm t",

We now need to adjust our githook. 

"config": {
  "ghooks": {
    "pre-commit": "npm run cover && npm run check-coverage"

One more spot in .travis.yml we need to make sure we run our cover script so it ends up looking like:

  - npm run cover
  - npm run check-coverage
  - npm run build


There we go! We now have an es6 friendly set up!

Next… UMD Build!

glyphicons-55-clock  = Time Saving Idea

glyphicons-499-sunglasses = Pro Tip

glyphicons-31-pencil = Note

glyphicons-197-exclamation-sign = Alert

glyphicons-424-git-create = Code Update

glyphicons-28-search  = A Closer Look