node-pg-migration is a useful library. You can add a constraint of a foreign key with a simple references property on the column. For example, you have table client_session with publishable_key column and you want to reference publishable_key column in workspace table where it is not a primary key (just a unique key). The following usage with object: schema, name, won’t work:
If you write a migration for Postgress and Node.js using node-pg-migration (e.g., table 1) and want to create a foreign key reference / constraint (createConstraint or references on createTable) on a non-primary key of the other table (table 2), then references by an object containing schema and table name, do not work. This is probably a bug in node-pg-migration. It tries to match primary keys only, but our publishable_key is not a PK in workspace.
It looks like node-pg-migration is not smart enough to add the column/field name like it does for primary keys. You can use a string (seam.table2(col)) as the references value, not an object, or just use raw SQL to bypass node-pg-migration behavior, e.g.,
I recently needed to update the check constraint on a Postgres table column. This check does format validation similar to regex. This check was part of the CREATE TABLE statement meaning it was created with the table.
However, ALTER COLUMN is not supporting updates of checks. So what we need to do is to drop the constraint and create a new one. dropConstraint requires the name of the constraint, but the name is not obvious. This is because check was create with createTable. To find the name, there’s a SQL query we can run:
SELECT con.*
FROM pg_catalog.pg_constraint con
INNER JOIN pg_catalog.pg_class rel
ON rel.oid = con.conrelid
INNER JOIN pg_catalog.pg_namespace nsp
ON nsp.oid = connamespace
WHERE nsp.nspname = '<schema name>'
AND rel.relname = '<table name>';
Over the past few months, I have been focusing on teaching cloud technologies with Amazon Web Services and other providers. I created a rather a large collection of resources which will help you to learn Amazon Web Services.
First of all, here’s a series of blog posts for total beginners with Amazon Web Services:
Amazon Web Services is de-facto a standard of cloud computing. Every software engineers should know at least its basics if not know it to an intermediate level.
I get this question very often: “What tools would you recommend for Node development?” Software engineers love to optimize and increase productivity instead of wasting their time. I bet you are one of them! Read on to find out the best Node tools for development.
IDEs/code editors
Libraries
GUI tools
CLI tools
IDEs/code editors
When it comes to your primary tool, the code editor, I recommend sticking with lighter and simpler editors like Atom or VS Code instead of full-blown IDEs like Webstorm. Of course an IDE will do more for you but this comes with a learning curve and the need to configure. Node is interpreted, thus there’s no need to compile it. The files are just plain text files with the .js extension.
title
Here’s my list of the best Node editors:
Atom: created and maintained by GitHub; uses Electron, HTML, JS and CSS under the hood which makes it very easy to customize or add functionality; allows to have Git and terminal support via packages. Price: free.
VS Code: a newer addition; uses similar to Atom web-based tech; was created from Azure’s Monaco editor; comes with debugging, smart autocomplete based on types, Git and terminal support. Price: free.
WebStorm: more of an IDE than an editor, developed by JetBrains and based on IntelliJ platform; has code assistance, debugging, testing, Git. Price: starts at $59/yr for individuals.
There are more options like Brackets, Sublime Text 3 and of course IDEs like Eclipse, Aptana Studio, NetBeans, Komodo IDE, and cloud-based like Cloud 9, Codenvy.
What to pick? Any of the three in the list is good choice. I have heard good things about VS Code and their smart autocomplete is a nice thing, but I didn’t find it a good enough reason for me to switch from Atom. So try VS Code and Atom and see which one you like more. Both of them offer a wide variety of packages and themes.
The most popular and useful libraries and project dependencies
Here’s the list of the most used and most popular modules which you would install as dependencies of your projects. Node developers use most of these modules (or alternatives) in almost all of their projects.
The libraries are listed with the npm names, so you can execute npm i {name} substituting {name} with the name of the package/module:
webpack: Builds static assets like browser JavaScript, CSS and even images. It allows to use node modules in the browser.
babel: Allows to code in the latest versions of JavaScript/ECMAScript without having to worry about your runtime by converting the new code to the code compatible with older versions of ECMAScript
async: Controls flow by running function concurrently, sequentially or any way you want
concurrently: Allows to execute CLI tools (local) as multiple processes all at the same time, e.g., webpack and node-static.
Note: Some of the libraries/tools listed above like webpack or mocha, can be installed globally instead of locally in your project folder. However, installing them globally is an old practice and currently is an anti-pattern because local installation allows developers to use multiple versions of the tool with different projects in addition to have these tools specified in package.json.
Of course there are a lot of different options in each category. For example, request and superagent are also extremely popular HTTP agent libraries. However, I don’t want to give too many options and confuse you with the differences, I listed only one tool (typically the one I use the most currently).
CLI tools (global)
pm2 in action
Unlike the previous section, these tools are okay to install globally since most likely their version won’t affect or break your project.
node-dev: Monitor and restart your Node app automatically on any file change within the current folder
node-inspector: Debug Node code in a familiar interface of DevTools (now part of Node starting with v7)
docker: Build and run Docker containers to isolate app environment, speed up deployment and eliminate conflicts between dev and prod (or any other) environments
curl: Make HTTP(S) requests to test your web apps (default for POSIX but can get for Windows too)
nvm: Change Node versions without having to install and re-install them each time
wintersmith: Build static website using Node templates and Markdown
pm2: Process manager to vertically scale Node processes and ensure fail-tolerance and 0-time reload
GUI tools
MongoUI in action
A good share of Node developers prefer GUI (graphical user interface) tools at least for some of the tasks because these tools require less typing and have features which makes them more productive and the development easier and simpler.
Postman: HTTP client with ability to save requests and history, change formats (JSON, form, etc.) and do other things
MongoUI: Modify and inspect your MongoDB data in a web interface. You can host this web app on your server to enable the database management.
Chrome: DevTools is a great way to inspect your requests, network, traffic, CPU profiles and other developer related data which is very useful for debugging
iTerm, itermocil and zsh: A better alternative to a native macOS Terminal app which together with itermocil and zsh increases productivity greatly
Recently I wrote a blog post and even created an online course on ES6/ES2015. Guess what? TC39—the mighty overseer of JavaScript—is moving forward with ES8 so let’s cover ES7 and ES8 (or ES2016 and ES2017 officially). Luckily, they are much, much, much smaller than the best of a standard that was ES6. Really! ES7 has only two (2) features!
ES7 features:
Array.prototype.includes
Exponentiation Operator
ES8 is not finalized yet as of this writing (Jan, 2017) but we can assume all finished proposals (stage 4) and most of stage 3 (more on stages here and in my course). The finished 2017 (ES8) proposals are:
Object.values/Object.entries
String padding
Object.getOwnPropertyDescriptors
Trailing commas in function parameter lists and calls
Async Functions
I won’t include stage 3 proposals in this post, but you can check the status of proposals from stage 1 to 3 here.
Let’s dive deeper into the proposals and features…
When Bert presented his keynote at Node Interactive Europe 2016 on Event Loop, he started by saying that most of event loops diagrams are WRONG. I’m guilty of using one of them in my talks. :)
This is it. In it, event loop is spinning data back at clients like hot-cakes.
His diagram is closer to the real stuff. In it, event loop starts, works and then quits eventually (pun intended).
Container technology is one of the best options for software development and deployment. It allows you to share some of the OS resources while encapsulating the code and other concerns. You can think of containers as virtual machines but with less footprint.
Containers are great for micro services where you replace monoliths with many services. Each of them works in isolation and communicates with other services via a well defined interface (typically REST).
Docker is one of the most popular implementations of containers. Docker’s What is Docker? page has a a neat comparison of containers with VMs. In a nutshell, VMs use hypervisor and each VM has it’s own OS while containers share OS and only separate libraries, bin, executables, etc.
This project will guide you through building an autocomplete function similar to the one that you might see in Slack (a popular messaging app), as shown in figure 1, when you type something in the search box. For simplicity, our widget will work with room names (the rooms in a chat application).
Figure 1
The autocomplete widget will have (figure 2):
An input field
A list of options filtered according to the entered characters
An Add button (figure 3)
Figure 2
The filtering of the matches will be done using the entered characters as the first characters of the option. In other words, there is a simple comparison that allows us to autocomplete the name of the room (figure X). For example, if you type “mac” and you have “Mac OS X” and “Apple Mac,” then only “Mac OS X” will be shown as a match, not both options.
In this book, I’ll introduce you to React Native for native mobile iOS and Android development… and do it quickly. We’ll cover topics such as
Why React Native is Awesome
Setting up React Native Development for iOS
Hello World and the React Native CLI
Styles and Flexbox
Main React Native UI components
Importing Modules into an Xcode Project
Project: Timer
Project: Weather App
This book is about getting started with React quickly and not about React Native, which is technically a separate library (or some might even call it a framework). But I figured after eight chapters of working with React for web development, it would be fun to apply our knowledge to mobile development by leveraging this awesome library. You’ll be amazed how many React Native skills you already know from React.
In the previous post, we learned how to perform HTTP/2 server push in a Node server. We also covered the benefits of server push there so to avoid duplication we won’t list them here. We used spdy for server push and H2. But most of the times Node developers don’t work with core HTTP server, they use a framework like Express. So let’s see how we can implement server push in Express.
HTTP/2 is the new standard of the web. It has many great features which will make the web faster and simplify the development. For example, no need to concatenate files thanks to multiplexing, or a server push which can send files before a browser knows it need them.
This post won’t cover all advantages of HTTP/2. You can read about them online. No need to go into all the details and duplicate text here. Instead, we’ll focus on server push and implement it in Node.js using Express and the spdy library.
The modern Internet with its TCP/IP protocol started around 1975 which is astonishing 41 years ago. For the most part of its existence, we used HTTP and it’s successor HTTP/1.1 (version 1.1) to communicate between clients and servers. It served the web well but the way developers build websites has dramatically changed. There are myriads of external resources, images, CSS files, JavaScript assets. The number of resources is only increasing.
HTTP2 is the first major upgrade to the good old HTTP protocol in over 15 years (first HTTP is circa 1991)! It is optimized for modern websites. The performance is better without complicated hacks like domain sharding (having multiple domains) or file concatenation (having one large file instead of many small ones).
There’s a better alternative to the ubiquitous JSON as the communication protocol of the web. It’s Protocol Buffers (protobuf). In a nutshell, protobuf offers a more dense format (faster processing) and provides data schemas (enforcement of structure and better compatibility with old code).
The purpose of this article is not to highlight why protobufs are better or sell you on the concept. There are many article online that’ll do it for you. The purpose of this article is to show you how you can get started with this format in the Node.js environment.
This post has been written by Scott Hasbrouck. You can find him on Twitter or his website.
It’s been nothing but wonderful to see JavaScript truly catch fire the past few years in web technology, ultimately becoming the most used language in 2016, according to StackOverflow data. My history with JavaScript began about 15 years ago, not all that long after it was first released as part of Netscape Navigator 2, in 1996. My most used learning resource was DynamicDrive, and their tutorials and code snippets of “Dynamic HTML” or DHTML – a term coined by Internet Explorer 4. Really, DHTML was a set of browser features implemented with JavaScript, CSS, and HTML that could get you nifty elements like rollover buttons and stock tickers.
Fasting forward to today, we now live in a world where JavaScript has grown to take over web technology. Not just in the browser, but it is now the most popular backend language according to that same StackOverflow report! Naturally, there are always those who dislike the language citing things like the ease of creating a global variable, or null being an object and undefined being its own datatype. But I’ve found that every language I pick up has quirks that are easily avoidable once you learn to properly use it. And we do want to become experts in our craft and truly learn to master our tools, do we not?
This essay was inspired by the Kyle Simpson’s series of books, You Don’t Know JavaScript. They are a good start with JavaScript fundamentals. Node is mostly JavaScript except for a few differences which I’ll highlight in this essay. The code is in the You Don’t Know Node GitHub repository under the code folder.
Why care about Node? Node is JavaScript and JavaScript is almost everywhere! What if the world can be a better place if more developers master Node? Better apps equals better life!
This is a kitchen sink of subjectively the most interesting core features. The key takeaways of this essay are:
Event loop: Brush-up on the core concept which enables non-blocking I/O
Global and process: How to access more info
Event emitters: Crash course in the event-based pattern
Streams and buffers: Effective way to work with data
Clusters: Fork processes like a pro
Handling async errors: AsyncWrap, Domain and uncaughtException
C++ addons: Contributing to the core and writing your own C++ addons
Event Loop
We can start with event loop which is at the core of Node.
Node.js Non-Blocking I/O
It allows processing of other tasks while IO calls are in the process. Think Nginx vs. Apache. It allows Node to be very fast and efficient because blocking I/O is expensive!
Take look at this basic example of a delayed println function in Java:
This is an excerpt from React Quickly (Manning, 2016). You can download the entire first chapter for free at Manning. The book is scheduled for release in the first quarter of 2016, but MEAP is available right now. Use code “mardandz” to get 39% off.
The project for this article will be minimal. The idea is to have a dynamically generated menu which will consist of <a> tags.
We’ll use custom React components Menu and Link. They way we create them is similar to the way we create the HelloWorld component in the previous example. The project will show you how to render nested elements programmatically. In the previous examples, we just coded the children manually. We’ll use the map() function for it.
Have you ever wanted to learn basics of Node.js and the most popular Node.js web framework Express.js? If you are experienced web developer or software engineer who wants to learn Node.js and build some servers along the way, then this self-study workshop is for you.
What is ExpressWorks? It’s an automated tool which allows to learn Express.js from the author of one of the best books on Express.js—Pro Express.js— with this workshop that will teach you basics of Express.js and building Node.js web apps (a.k.a. servers).
You will walk through adventures via command-line interface. Each adventure has a problem, hints, and the solutions.
I hated Jade as many other Node.js developes do. But I changed 180 after I realized that it has tons of features.
At Storify and DocuSign we used Jade for EVERYTHING. We used Jade even in the browser. There is a little trick called jade-browser. It was developed by folks at Storify. I maintained it for a bit.
The funny thing is that DocuSign team used jade-browser long before they met me. They swear they hired me without knowing that I was involved in that library. :-)
Anyway, after covering Jade and Handlebars in previous posts, it’s time to apply them to do some real work. In this post, I’ll cover:
Getting a job of your dreams might be easier than you think. Apply these five hacks and see for yourself.
Study after study has showed that being satisfied and happy at a job is paramount for a healthy, productive and long life. In other words, if you’re miserable at a job, then other areas of your life will suffer as well: personal life, health, spirituality, family, friends, etc.
Here are the 5 Hacks that will help you to get your dream job:
Write a book
Create a strong web presence
Boost your LinkedIn profile
Speak at a conference
Take a MOOC (Massive open-online course)
You can use these five hacks to get the job of your dreams in pretty much any industry or field. And most of them will cost you nothing or close to nothing!
Of course, any of these hacks are useless if you don’t know what your dream job is. If you are not sure, then before reading any further, answer these questions:
How much money do you want to make in a year or an hour?
How much maximum commute can you tolerate (e.g., 30min, 1hr)?
Do you like a certain area of your city?
Do you want to work with certain technologies or in a particular industry?
What kind of benefits do you want to have (ideally)?
Go crazy with these questions, let your fantasies go wild… yet remain realistic, otherwise you won’t believe it’s possible.
We are not separate people when we go to work and come back from it. We cannot separate our jobs from the rest of our lives. The quality of your job and its factors are in direct proportion to your happiness and physical and mental health.
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