Tutorial for setting up the coding environment

This page is a brief tutorial on where to find information about the coding languages used in visualisations, as well as how to set up a visualisation.

Setting up the coding environment

The Languages

Hypertext Markup Language (HTML) is the backbone of any webpage, and this is the case for Imperial Visualisations. HTML is less of a language and more of a collection of blocks or ‘elements’ that define what goes on your page. HTML allows us to define everything on our page, but cannot do much else. For the most part, HTML is static and cannot perform complex equations or plotting. This is where JavaScript (JS) comes in. Imperial Visualisations uses JS to perform physical/mathematical calculations, plot, and achieve interactivity. These elements can contain anything from text to a slider to a graph plot, and can be styled to your preference! From the size of your element to the text color, this styling can all be specified using another language: Cascading Style Sheet (CSS).

Here are a few Links to relevant places on how to do some basic HTML, CSS and JS -

• HTML: https://www.codecademy.com/learn/learn-html
• CSS: https://www.codecademy.com/learn/learn-css
• JS: https://www.codecademy.com/learn/introduction-to-javascript

For the HTML course, you will most likely require sections 1. Elements and Structure, and 3. Forms. You may choose to opt-out on learning CSS as we have a set of predefined components, like sliders and buttons, which will be introduced later! If you are interested in customising the components, you may come back and learn CSS. As for JS, sections 2-7 are essential, and sections 8 and 9 are useful for object-oriented programming.

While coding a visualisation, you will inevitably have to use some mathematical functions. Math.js is an extensive JS math library that provides many useful tools. For more information, https://mathjs.org/.

***From here, we will assume knowledge of basic HTML and JS.***

Visual Studio Code

VSCode welcome

Download: Visual Studio Code (VSCode) is the integrated development environment that we recommend. Still, you are free to use any code editor that supports JS and HTML. To download VSCode, please visit https://code.visualstudio.com/download. After installing and opening it, you should find this as your welcome page (right).

VSCode hello world.

Creating a basic HTML and opening a folder in VSCode: On the top left, click on File > New File, and you should get an empty file called Untitled-1. Include the code in the following example and save it as some_name.html.

Now, open the file in a web browser (e.g., Google Chrome), you should see the the stuff on the image below:

Hello world display

VSCode folders

If you have created a folder for your HTML, you may want to open the VS Code folder. You can do it by dragging the folder into the Explorer:

Live server

It is often convenient to see changes on your website while editing. For that purpose, we make use of the live server. Click on the extension button, search for Live Server, and install it.

Live server

Once you have done that, go back to the HTML file you have created and click on the ‘Go Live’ button on the bottom right.

Hello world going live

Hello world displayed on live server

Your HTML file will be opened in your default browser now. You can put the browser and VSCode side by side and see the changes being done live (after saving your changes). You may utilise the autosave function (in the File dropdown) if you like.

To stop the Live Server, click on the ‘Port: 5500’ cancel button (at the bottom right).

Creating a visualisation

The best way to create visualisations is to use the create-impvistool, which automatically sets you up with a project folder with a working template and git repository already set up! The create-impvis tool can be installed once you have Node.js installed by using the Node Package Manager (NPM). To check that you have both of these programs installed correctly on your computer, you will need to open a terminal window and run: node -v && npm -v

If Node.js and NPM are correctly installed on your system, you should see two version numbers printed (the exact number doesn't matter). With Node and NPM setup on your machine, you can install the CLI by running globally: npm -g install @impvis/cli and wait for the CLI to be downloaded and installed on your machine.

Usage

Creating Visualisations with the Vue CLI is a breeze! To create a visualisation, open a new terminal window in the directory you wish to create the visualisation folder. Then run: impvis create name

Where name is the name of your visualisation (decide that here). You will then be guided through step by step prompts to allow you to configure the base visualisation template to suit your needs. At present, the CLI has four template options available for users to choose from:

1. Current template using Node.js
2. Current template using a <script> import
3. Basic legacy template from Summer 2019
4. Advanced legacy template from Summer 2019

If you're new to ImpVis, we recommend the first option.

Running Your Vis

When you want to run your visualisation, navigate to the folder where you created it in command prompt or terminal and run the command, npm run serve. The project will then build and you should be able to open it by navigating to one of the adresses shown in your browser. Any changes to the code will now be shown in real time. To end the server press "control + C" in the command prompt.

The 2020 template using Node.js

To see more about the current template, view Vue Components. For a brief tutorial on the basic components of the components used in the current template, view Basic Component Tutorial.

This template is the recommended template for all new projects from now on as it comes with a pre-configured node.js instance, which makes running automated tasks, linting your code for errors, and optimising your code for all browsers a breeze. It also includes the Imperial Visualisations Vue Components library as standard, already set up and ready to go! Using this template, you will create visualisations using the Vue Single File Component files (.vue), which allows you to divide your visualisation up into sub-components, each containing all the HTML, JS, and CSS needed for the component to function correctly. For a refresher on how components work, you should check out the Introduction to Components video on the ImpVis Youtube channel.

Installing additional packages.

Using this template, it is easy to install additional modules after the fact simply by running: npm install my-package-name, where my-package-name is the name of the package containing the modules you want to install. This automatically downloads and installs the relevant package from the NPM repository. You can then use ES6 import statements to access the features of the library.

The 2020 template using script tag

This template is recommended for people new to or just getting started with Vue.js. It removes some of the additional complexity associated with a Node.js backend. In this template, you work entirely within a single .html file with Vue and the Imperial Visualisations library included with standard script tags located in the header.

Installing additional packages.

Installing additional packages for this template is not as convenient as using the Node template however is still relatively simple. The UNPKG repository can quickly retrieve a valid URL for any library located on NPM. Additional dependencies can be added to the head section of the HTML file by writing: < script defer src="https://unpkg.com/<my-package-name>/@version-number

You may need to read the library documentation you are importing to see if there are any additional files such as CSS files that also need to be imported.

Legacy templates (Basic & Advanced)

These legacy templates are not recommended for most people who want to create visualisations. They do not contain the modern Vue component library created by the ImpVis team to help develop visualisations. These templates are, however, useful for those who wish to get a simple, no batteries included environment to play around with or for those who need a starting spot to upgrade old visualisations located on previous versions of the ImpVis website. This template comes with the Math.js library preloaded for this reason, as it is a popular library with many of the old visualisations. For those who are editing older visualisations from pre-2020, check out 2019 style template and 2017-2018 style template.

Installing additional packages.

Additional dependencies can be installed using the same manner as described above for <script> templates.