This glossary is ever-evolving
and relies on contributions
from people like you
for improvements and new term suggestions ❤️.
If you don't find the word or technical term you
you are searching for,
please create an issue:
github.com/dwyl/technical-glossary/issues
Have you ever learnt something new without knowing what it's actually called? Or have you ever been reading about a concept only to get lost in the number of acronyms and other technical words used to describe what you're learning about? 🤔
This resource provides quick access, simple and easy to understand definitions to stop big words getting in the way of what could be happy learning 😊
A technical glossary for key words you will encounter in your journey through learning creative technology. These definitions are deliberately succinct, they aim to be easy to understand and bite-sized for quick access. In some cases we include links where you can read more on a given topic.
Scan down the alphabetically ordered list to learn about key words. If you don't find the word you're looking for, or want to expand on a definition, please open an issue with your questions / suggestions.
Adaptive Web Design (AWD) encourages the creation of several versions of a web page for a specified number of device dimensions. Which template to display is determined in the HTTP GET request which recognises the screen size of the device. Adaptive Web Design was introduced to deal with mobile browsing when most sites were optimised for desktop only.
Authentication is the process of verifying that you are who you say you are E.g. when you login to your email you use a password to authenticate your identity. Other methods for authentication include using an ID card or fingerprint/biometric method.
Note: the authentication experience can be a significant source of frustration both as person using a digital product and for the engineers building it. We decided to build our own Single Environment VariableTM drop-in solution to the problem: dwyl/auth
Authorization is checking that the person
is authorised (has permission)
to access a given page/resource
or to perform a certain action in an App.
e.g: a person with admin permissions
is authorised to view logs in the App.
In JavaScript declarations
are var, const and let
for the creation of variables, constants
and lexically scoped variables.
The scope where a variable can be accessed. A function used within another function can access the parent function's variables since its scope extends to its parent.
In this example, the variable color
is accessible to the function displayColor().
function showColor() {
const color = 'red';
function displayColor() {
alert(color);
}
displayColor();
}See: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Closures
The concept that in HTML all elements are contained within rectangles or boxes. Each box consists of: margins, borders, padding, and the actual content.
See: https://en.wikipedia.org/wiki/CSS_box_model
A CRM system allows organisations to manage customer relationships and the data and information associated with them. Typically a CRM is used for storing contact data and the log of communication between a business and its' customers. But increasingly CRMs are used for other functions in businesses such as sales tracking, customer service and customer portals.
See: https://en.wikipedia.org/wiki/Customer_relationship_management
CRUD refers to the 4 basic operations you can perform in a database or application that process data. Create a new data entry, read or retrieve existing data from the database, update the value of an existing piece of data or delete an existing item of data.
See: https://en.wikipedia.org/wiki/Create,_read,_update_and_delete
CORS is a specification that allows specified resources on a web page to be requested from another domain outside the domain from which the first resource was served. E.g. uploading images using different domains using Amazon S3. For more about origin policies see 'Same-origin Policy'. See: https://en.wikipedia.org/wiki/Cross-origin_resource_sharing
Destructuring Assignment is the ability to unpack and assign variables when there are multiple parameters.
A way to simply assign the variables and then swap their values.
let x, y;
[x, y] = [5, 6];
// x = 5, y = 6
[y, x] = [x, y];
// x = 6, y = 5To assign values from an object.
let obj = { 'a': 1, 'b': {'b1': '1.1'}}
let {a, b, b:{b1}} = obj
// a = 1, b = {'b1': '1.1'}, b1 = 1.1There is an extensive list of examples on this StackOverflow answer: https://stackoverflow.com/questions/54605286/destructuring-assignment-uses
The characters/words used to identify a website
after https:// or www..
The domain name consists of two parts.
Take this example:
https://dwyl.com,
dwyl makes up the second level domain (SLD)
which is then followed by .com
which what is known as the top level domain (TLD)
or parent domain.
Other examples of top level domains are:
.org, .co.uk or .io.
Domain names are the more memorable
and user-friendly representation of a website's IP address.
Domain names are registered under the Domain Name System (DNS).
A distributed global directory of website domain names (and other internet resources). The directory stores already registered domain names along with their corresponding IP addresses.
Hexadecimal Uses 16 different symbols: "0"-"9" and "A"-"F" to encode data. It's common to use hexadecimals when working in CSS to assign colors to your elements.
The hexadecimal for dwyl's logo color is
#4bc0a9
(teal).
To convert the hexadecimal into RGB values, do the following:
R = 4b
G = c0
B = a9
Convert the letters to their numerical value.
b = 11
c = 12
a = 10
Red: 4 * (16^1) + 11 * (16^0) = 75
Green: 12 * (16^1) + 0 * (16^0) = 192
Blue: 10 * (16^1) + 9 * (16^0) = 169
Hex: #4bc0a9 is RGB: 75, 192, 169.
Hoisting is JavaScript's default behaviour
of moving var declarations
to the top of the current scope
when your code is run.
What this means is that whatever line you write a var declaration on
e.g. var x;,
when your code is run
it will automatically be lifted
and read as if it were written on the top lines of your current scope
(to the top of the current
script or the current function).
This means that you can use var's higher up in the code before the line you've
declared them on. So this example:
x = "hello";
console.log(x) // logs 'hello'
var x; // declaring `x` which is hoisted as if it were written at the top on compilationIs read by the computer like this:
var x; // declaring `x` which has been hoisted to the top line on compilation
x = "hello";
console.log(x) // logs 'hello'This is obviously confusing/undesirable code, please don't do this!
Higher-order Function
are functions that take other functions as parameters
and/or return a function.
Some examples of these types of functions are the
map and
reduce
method used for arrays.
They both accept a function to use on the elements in the given array.
// perform an action twice
function twice (func, value) {
return func(func(value));
}
// func can be any simple (preferably pure) function:
function func (value) {
return value + 3;
}
console.log(twice(func, 1)); // 7
console.log(twice(func, 7)); // 13Not to be confused with "pure" functions. To understand the difference, please see: dwyl/learn-redux/issues/40
Hypertext Transfer Protocol (HTTP) is the set of rules for transferring files (text, graphic images, sound, video, and other multimedia files) on the World Wide Web. When you enter http:// in your address bar in front of the domain, it tells the browser to connect over HTTP.
Defining a variable and providing it with an initial value: e.g:
var x = 1;A unique series of numbers or hexadecimal digits used to identify a website.
See: https://en.wikipedia.org/wiki/IP_address
JSON (JavaScript Object Notation) is a lightweight data-interchange format. It is easy for humans to read and write. It is easy for machines to parse and generate. It is based on a subset of the JavaScript Programming Language Standard ECMA-262 3rd Edition - December 1999. JSON is a text format that is completely language independent but uses conventions that are familiar to programmers of the C-family of languages, including C, C++, C#, Java, JavaScript, Perl, Python, and many others. These properties make JSON an ideal data-interchange language.
JSON syntax is derived from JavaScript object notation syntax:
- Data is in name/value pairs
- Data is separated by commas
- Curly braces hold objects
- Square brackets hold arrays
In JSON, values must be one of the following data types:
- a string
- a number
- an object
- an array
- a boolean
- null
Example of JSON data:
{
"id": 101,
"fullName": "John Doe",
"skills": ["Javascript", "JAVA", "Python"],
"isVerified": true
}See: https://en.wikipedia.org/wiki/JSON
The practice of splitting the business logic of your App/business into multiple distinct self-contained services and deploying them individually. It is a widely accepted/used application architecture. Lambda Functions are an example of a micro Node.js Server.
See: https://en.wikipedia.org/wiki/Microservices
The ability for an object to take on many forms or types e.g: when a parent class is used to refer to a child class object. Operator overloading is one form of polymorphism. It is not used in Javascript but is a feature of C++, Scala, Ruby, Haskell and Rust.
See: https://en.wikipedia.org/wiki/Polymorphism_(computer_science)
PWAs are traditional websites that are enhanced with modern web technologies, allowing them to provide a more app-like experience. They offer functionality such as being saved as a tile on your mobile home screen, working offline and push notifications. The “progressive” part means they’re “progressively enhanced” with newer features, which means they’ll also work in older browsers that don’t support the new features. Unlike native apps, they don't have to be updated/listed in the app store although it is possible to list them in the app store when this is desired.
Regression Testing - the re-running of existing tests to ensure that new changes/fixes have not broken any existing functionality. We should perform regression testing any time we modify an application, automated testing is a convenient way to achieve this.
REPL (READ, EVAL, PRINT, LOOP)
is an interactive programming language shell.
A simple, interactive computer programming environment
that takes single user inputs (i.e. single expressions),
evaluates them, and returns the result to the user.
They are a handy tool for experimenting with
functionality outside of the context of a project.
Most programming languages have them.
In JavaScript you can type node in your terminal
and then type any expression e.g:
> console.log("Hello World!")
Hello World!Similarly in Elixir we have iex:
iex
iex(1)> IO.inspect("hello world")
"hello world"Responsive Web Design (RWD) is the practice of designing one version of a web page which reorders and resizes content in response to the size of a browser at any given point, not just predetermined device sizes. This means the design of the site is optimised for all screen sizes. See Adaptive Design for another approach to designing.
The security policy implemented by web browsers, whereby a document (i.e. like a web page) hosted on a server can only interact with other documents the same server.
Search Engine Optimisation (SEO) is the process of improving the visibility of a website or web page in unpaid/organic search engine results. There are many aspects to SEO and search engines change how it's calculated over time. It may include the use of key words on a page, how often you add/edit content on your site, to the way other sites link to you on the web.
Semantic HTML is the use of HTML elements
that accurately describe
what they contain/are being used for
E.g: a <p> tag indicates that the text within it is a paragraph
whereas a <nav> tag should contain navigation content
and a <footer> should appear at the end of the page.
A spike is a product development method that uses the simplest possible experiment to explore potential solutions to a problem. It can be just a basic design/interface test (wireframe) or a technical exploration often called a proof of concept (POC). See: https://en.wikipedia.org/wiki/Spike_(software_development)
Remember a problem well-stated is half solved so define the problem you're trying to solve with your spike before attempting to solve it. e.g: by creating an issue to capture the requirements.
@dwyl our spike mini-projects
are usually time-boxed
anything from an hour to a day of effort.
The objective is to capture the learning
as much as it is to test the interface or technical implementation.
Therefore we always create a new GitHub repo to capture the experiment.
Sometimes we will include the word "spike" in the repo,
e.g:
dwyl?q=spike
Other times, we will expand the repo into an example app
that is more of a tutorial that anyone can follow,
e.g:
dwyl/repositories?q=example
We have plenty of recent examples of single-feature
spike experiments,
but we have been capturing our learning this way for a long time,
e.g:
dwyl/meteor-search.
However much detail you include in your spike, remember that the objective is to communicate what you tried so that other people can replicate the experiment. It's not enough for you to know that it worked (or failed), you need to share everything you learned along the way. If you skip steps in your log of the spike so other people
Syntactic sugar refers to syntax in a language that is
designed to make things easier to read. The syntax makes the language "sweeter"
to use as things can be expressed more clearly or concisely. Something can be
considered "syntactic sugar" if it could be removed from the language without
removing any functionality on what the language can do. For example ternary
operators in Javascript: x ? a : b doesn't require the ternary operator syntax
it could also be expressed with an if/else statement:
if(x)
{ a }
else
{ b }Technical Debt is the time/cost of "re-working" a feature (or entire app) because corners were cut the first time it was built. Think of Technical Debt like a "loan shark" for your project, if you take "shortcuts" to implement a feature quickly (e.g: by skipping tests) you will pay for it later and usually with "interest". For more detail see: https://github.com/dwyl/product-owner-guide#what-is-technical-debt
Transmission Control Protocol (TCP) is a protocol which exists to enable the establishment of a connection and the exchange of streams of data (multiple data packets) between one or more computers. TCP guarantees the delivery of data and that packets will be delivered in the same order in which they were sent.
A Transmission Control Protocol (TCP) handshake is the first part in a three part process for TCP data transfer between a local host/client and a server. The handshake is a three-step method that requires both the client and server to exchange SYN and ACK (acknowledgment) packets to establish a connection before actual data communication begins.